A brief entry in the Microsoft blog has announced that Windows Vista SP2 will be available “sometime” in Q2-2009:
SP2 for Windows Vista and Windows Server 2008 include updates that have been delivered since the release of SP1, as well as support for new types of hardware and emerging standards. As we’ve described since we first talked about SP2, we’ve taken your feedback into account when developing SP2. Specifically, we expect SP2 to continue the security benefits of both products and simplify deployment for our customers.
The link that I referenced above also has a list of the things that SP2 will do. The list is very long, but it is worth reading if you’re a user of Vista. Oh, for those of you with testicles of steel brave enough to try it, a release candidate will be available to the public.