Check out the links below. Its pretty simple to use. Once you have created your Web.sitemap file in your project or solution, then you can bind this to the Navigation controls that are in your Toolbox. I like to use the SiteMapPath or Menu controls. Just drag the control onto your page and then a wizard dialog will appear asking you for a datasource, reference your Web.sitemap file and then you should be set to go. Now the structure of your navigation will be reflected in your Web.sitemap file. Remember this, there can be one root sitemap node.

http://weblogs.asp.net/scottgu/archive/2006/01/11/435108.aspx

http://weblogs.asp.net/scottgu/archive/2005/11/20/431019.aspx

http://www.w3schools.com/aspnet/aspnet_navigation.asp

I hope this helps.