App-V 4.5 SP1 RTMs
As the App-V landing page suggest, App-V 4.5 SP1 is out (late october has passed it seems).
The release notes make interestinng reading. Most anticipated are support for the Windows 7 and 2008 R2 platforms. The Applocker feature is interesting, and Tim explains here a potential use.
64bit support is absent, but not expected until 4.6 arrives next year (see support table).
The 4.6 Beta is available though.
I won't be suprised if it is available along with office 2010 - other sites have suggested as much 