Example 3 - Customizing the top link bar
To add a new item to the top link bar of your SharePoint team Web site, do the following:
In the Program Files\Common Files\Microsoft Shared\web server extensions\50\Templates\1033\xml directory, open ONET.XML.
At the top of the ONET.XML file, find the TopMenuItems section. The first item listed in the collection corresponds to the item that appears farthest to the left on the link bar.
Add a new node where you would like the new item to appear on the link bar, including the file name of the page you want to link to, such as follows:
<TopMenuItem Name="NewNavigationItem" DisplayName="New Navigation Item" Url="_layouts/NewNavigationItem.htm"/>
Note The URL is relative to the root of the SharePoint team Web site.
Add your new page to the Program Files\Common Files\Microsoft Shared\web server extensions\50\Templates\1033\Layouts directory.
Create a new subweb.
All new sites will contain your new page in their individual _layouts folder within the wwwroot directory, and the top link bar will now include a link to the new page.