You can find the latest MP road map here.
As you will see the windows 2008 will soon be available in Beta on the Connect site!
Another thing to mention is the mp for Exchange 2007 sp1. It should be available since April/08 but it isn’t!! @ the moment, the mp for exchange 2007 gives us a lot of trouble with Exchange 2007 sp1. Some performance counters are not collected, heathservice running at 30%, no topology view, etc etc. So I’m really looking forward to it!