If you are coming to PDC and are expecting something special from the C# team, you won't be disappointed. My colleague Matt has already given as much of a preview as we can (to avoid spoiling a good surprise), so I will stick to the sessions to watch and things to do. Further details are on PDC site and real bits to use on the PDC DVD (and on the site mentioned below after PDC).
There have been some wildly speculative and inaccurate blog posts out there about what is in C# 3.0 and VB 9.0 and where it comes from. So instead of searching around for tidbits, come to the sessions.
Not at PDC - don't worry - we will have the following site up soon after unveiling it at PDC. http://msdn.microsoft.com/netframework/future/linq (you will get 404 errors until it is ready for disclosure. So check it on Wednesday/Thursday 9/14-15)