In the LINQ preview (CTP May 2006), the Smart Tags functionality in the C# IDE does not work correctly. In particular, I miss the "Resolve" feature that puts in the necessary "using" statements automatically. But the good news is that it is easy to get...

Read about it here: http://msdn.microsoft.com/netframework/future/ Or go directly to the download page: http://www.microsoft.com/downloads/details.aspx?familyid=1e902c21-340c-4d13-9f04-70eb5e3dceea&displaylang=en