I recently co-authored an Information Office Worker book on how to use Windows SharePoint Services published by Microsoft Press called Microsoft® Windows® SharePoint® Services Step by Step (ISBN 0-7356-2075-X). However, some of the content that I wrote was deemed “too technical” for the audience and cut from the book. So as not to waste the content, I've pasted some verbage I wrote on Custom Templates below. The text hasn't been thru editorial, technical, or even peer review so it is pretty raw and there are references to the GardenCo site that you won't have (really any site with a Task list will do) but I thought it would be worth sharing anyway.
Custom Templates
Site templates are used in Microsoft Windows SharePoint Services as a blueprint to jump start a new site's usefulness by auto-generating the Web Part Pages, Web Parts, lists, and document libraries that will likely be most useful in a given situation. In this chapter, you will learn how to create a site using one of the site templates that are available from a default installation and the steps necessary to manage and administrate this site.
Saving and using a site template
After working with a site for a while you may want to save it just the way it is so that it can be recreated over and over again. Microsoft Windows SharePoint Services facilitates this activity by letting the Web Designers and Administrators save a site as a custom template. Custom templates are a way of packaging up a set of changes to an existing site definition and making that package available as a template for new sites and lists. These custom templates behave in much the same way that the eight built-in templates do in that they provision Web Part Pages, Web Parts, lists, and document libraries best suited for the purpose of the template. In fact, everything in a site, except security related information is saved in a custom site template, including its theme and navigation. You can even optionally retain the data in all the site's lists and document libraries.
The STP files on this book’s CD used to recreate the solutions for each chapter are actually custom site templates saved to a file.
There is currently a 10 MB limit on the total size of any custom template.
Every custom template is based on an underlying site definition and saved as a file in the site collection site gallery document library in the root of the site collection. Once saved, a custom site template is made immediately available throughout the entire site collection in which it was saved. When creating a new child site, any user that is associated with one of the default site groups (excluding the Guest site group) in the top-level site will see the saved custom site template as an option on the Template Selection page. To use a custom site template when creating a new top-level site from SharePoint Central Administration it must be placed into the central template gallery using a command line tool on the Web server rather than just in the site collection site gallery.
Let's say that the unique look that The Garden Company buyers created for their team meetings has caught on and they want to be able to use it over and over. In this exercise, you will save the Team Meeting site as a custom site template and then use it to create another meeting site as a child of the Buyers child site.
OPEN the Team Meeting site from the address bar of your browser: http://gardenco/buyer/TeamMeeting. If prompted, type your user name and password and click OK.
BE SURE TO verify that you have sufficient rights to save a site template and create a new site. If in doubt, see the Appendix on page XXX.
1. Click Site Settings from the Modify This Workspace menu just below the search box on the Team Meeting child site.
2. Click Go to Site Administration in the Administration section to display the Site Administration page.
3. Click Save site as template in the Management and Statistics section to display the Save Site as Template page

4. Type TeamMeeting in the File name textbox to establish a name for the STP file.
5. Type Team Meeting Template in the Template title textbox to establish the name that will show in the list of templates to choose from on the Template Selection page.
6. Type a description like: Cool blue site for team meetings that the buyers created in the Description textbox to help site creators understand the intended purpose of the custom site template.
7. Click the OK button to save the custom site template into the site collection site template gallery and display the Operation Completed Successfully page.

If you want to see where the custom site template was placed you can click on the site template gallery link on the Operation Completed Successfully page.
8. Click the OK button to acknowledge the page and redisplay the Team Meeting Site Administration page.
9. Click Up to Buyers in the top right corner to display the Buyers child site.
10. Click Site Settings on the top nav to display the Site Settings page.
11. Click Manage sites and workspaces in the Administration section to display the Sites and Workspaces page.
12. Click Create on the toolbar to display the New SharePoint Site page.
13. Type Important Meeting in the Title textbox to establish a display name for the new site.
14. Type a description like: Site for that important meeting in the Description textbox to help users understand the purpose for the new site.
15. Type ImportantMeeting for a Web Site Address into the URL name textbox. Remember the naming conventions listed earlier in this chapter.
16. Keep the default permissions; Use same permissions as parent site.
17. Click the Create button to display the Template Selection page.
The Team Meeting Template is now available in the Template list. Also note that the description we gave to the custom site template is displayed below the image.

18. Click Team Meeting Template on the Template list.
19. Click the OK button to template and display the new meeting workspace.
The new site Important Meeting site will be identical to the original Team Meeting site.

Saving and using a list template
After you have placed a lot of effort into customizing a list so that it meets your specific needs, as is the case with our Common Buyer Tasks list, you may want to save that effort in a way that it can be used just like one of the built-in Microsoft Windows SharePoint Services list templates. Fortunately, this is very easy to do.
You can optionally include content in the list template if you want new lists created from to include the list items. Of course, including content can increase the size of the template.
There is currently a 10 MB limit on the total size of any custom template. Also, list item security is not maintained in a list template.
The Garden Company buyers would like the Common Buyer Tasks list to be made into a list template named Buyer Tasks Template that would automatically be included on the list Create page. The buyers would use the list template to create a new list whenever they launch a seedling buying campaign and the new list would look just like the current Common Buyer Tasks list. It would have the same columns, the same data, and the same list views.
In this exercise; you create a list template named Buyer Tasks Template based upon the current Common Buyer Tasks list. Subsequently, you will create a new list based upon the saved list template.
OPEN the top-level site for The Garden Company: http:// gardenco. Authenticate as at least a Web Designer.
1. Click Common Buyer Tasks in the Quick Launch bar to display the Common Buyer Tasks default list view page.
2. Click Modify settings and columns in the Actions section of the left nav to display the Customize Common Buyer Tasks page.
3. Click Save list as template in the General Settings section to display the Save as Template: Common Buyer Tasks page.
4. Type BuyerTasksTemplate in the File name textbox.
This is the name of the STP file that will be saved into the List Template Gallery for the entire site collection.
5. Type Buyer Tasks Template in the Template title textbox.
This is the name that will be displayed on the list Create page.
6. Type something like: Create a buyer tasks list when you launch any seedling buying campaign. in the Template description textbox.
This is the description that will show below the name on the list Create page.
7. Click the Include content checkbox to be sure that the list items in the list are captured with the list template.

8. Click OK to save the Buyer Tasks Template into the site collection’s List Template Gallery.

9. Click Create in the top nav to jump straight to the Create page.
10. Click Lists in the left nav of the Create page.

11. Click Buyer Tasks Template to create a new list based upon the list template that we saved and display the New List page.
12. Type 2004Q4BuyerTasks in the Name textbox.
13. Type something like: Fall buying campaign. in the Description textbox.
14. Leave Yes selected for Quick Launch display.

15. Click Create to provision the new list and display the 2004Q4BuyerTasks default list view page.
16. Optionally, rename the list by clicking Modify settings and columns in the Actions section of the left nav to display the Customize 2004Q4BuyerTasks page.
17. Click Change general settings at the top of the General Setting section to display the List Settings: 2004Q4BuyerTasks page.
18. Replace 2004Q4BuyerTasks by typing 2004 Q4 Buyer Tasks in the Name textbox.
19. Click OK to save the name change and display the Customize 2004 Q4 Buyer Tasks page.
20. Click Go Back to "2004 Q4 Buyer Tasks" at the top of the page to redisplay the 2004 Q4 Buyer Tasks default list view page.

Changes made to the original Common Buyer Tasks list do not affect this new 2004 Q4 Buyer Tasks list and vice versa. Changes also do not affect the Buyer Tasks Template list template. It is possible to resave the list over the existing list template effectively updating it.