Microsoft held a big teleconference today, which I unfortunately got called away from a minutes into it. The call was basically the launch of SQL Server R2. There are numerous posts from floating around from some high profile community members:
Brent Ozar’s post is here
Mr Denny’s Post is here
From what I can gather there is an evaluation copy available to download today, Technet and MSDN subscribers get it on 3rd May and Volume License customers get it later on the 13th may. Check out the above posts for more detailed, probably more accurate info though, I did miss most of it after all.