Yes, I know it's a bit late but I didn't realise it had been Released To Web until Windows Update prompted me to install it today.
From The Windows Blog:
"Consumers with Windows Vista SP1 can visit the Microsoft Download Center or use Windows Update (WU) to install SP2, but my suggestion is to turn on Automatic Update (AU) and sometime during the coming months your computer will download and install SP2. Similar to previous releases, SP2 delivery over Automatic Update is a “throttled release” which will begin in June."
I can't find any references to changes for MSMQ but that's not too surprising - as mentioned back in April, there have been no post-SP1 hotfixes released that would be packaged up in SP2.