The May 2006 CTP for LINQ is now live. See the .Net Framework Development Center for more information. I will probably be using the January CTP for the Code Camp presentation this weekend, but will look forward to trying out the new features and letting you know what I think of them as soon as I can.

Update: There is already a flury of postings around the new build. Paul Vick has a blog posting listing the main changes. Also, see the XLinq team's blog for more information.