The Official SBS Blog : How to Install Exchange 2007 Service Pack 2 on Windows Small Business Server 2008:
Couple of things here… first there is no rush for this. It’s a service pack on a major email database with no uninstaller. There will be a unique wrapper for SBS. There’s no NEED AT ALL to put this on a SBS 2008 production system at this time.
So no one be installing this at lunch time… got it?