Well, not what I'd call a big update to MPS reports but still worth noting if you intend gathering diagnostic data for a 64-Bit environment.
The download page for MPS report has been updated (following a recent discovery on a x64 PoC) to reflect that some of the MPS tool variants support 64-Bit e.g. the MPS report tool for SQL Server. The important notes section previously stated that the tools do not support 64-Bit. Refer to the important notes section listed here: http://www.microsoft.com/downloads/details.aspx?FamilyID=CEBF3C7C-7CA5-408F-88B7-F9C79B7306C0&displaylang=en "Not all MPSReport versions are currently supported to run on 64bit Operating system versions. Please view associated readme.txt for specifics".
The PFE variant also fully supports a 64-bit environment http://www.microsoft.com/downloads/details.aspx?familyid=00ad0eac-720f-4441-9ef6-ea9f657b5c2f&displaylang=en