Now is the time to try out your profiler against the new .NET FX 4.0 Beta 1 bits.  I'll be writing about some gotchas, and how to take advantage of the new features.  But first, get started downloading:

Visual Studio 2010 Product Page

You can find some reference documentation on the new profiling interfaces here:

http://msdn.microsoft.com/en-us/library/ms404386(VS.100).aspx