Dynamic Data is a very nice feature for developping rapid administration interfaces.
Scott explains how to create a new on in an existing project
http://blogs.msdn.com/scothu/archive/2008/06/23/how-to-add-dynamic-data-to-an-existing-web-site.aspx
Another walkthrough from msdn :
http://msdn.microsoft.com/en-us/library/cc668188.aspx
