One of the questions we got during the Q&A of the Ottawa VS Launch yesterday was around problems in migrating ASP.NET applications from 2002/2003 to 2005.
The Web Platform Team has put together a nice step-by-step guide that covers some best practices to ensure a successful migration effort which should take you “the better part of a day” according to them. http://msdn.microsoft.com/asp.net/default.aspx?pull=/library/en-us/dnaspp/html/webprojectsvs05.asp