Soon after the first beta build was sent out, Redmond told testers that it was planning a release candidate build and a final build then a more concrete date will be chosen based on the feedback the company receives during the service pack beta testing process.
In December 2008, a public beta of SP2 was released. Microsoft is expected to have at least one more public beta build released before SP2 goes RTM.
Due to unknown release date and narrow details beyond what Microsoft said, speculations and rumors spread. Rumors say that SP2 Release Candidate was coming in February and that SP2 should RTM in April and that rhe actual release candidate build has now been delayed till March. The RTM build of Service Pack 2, which was originally scheduled for April, has been delayed until sometime in Q2, 2009. That means a launch in either May or June, barring any further delays.
Despite of any problem about SP2 updates, Microsoft is concentrating on replenishing for the un-awaited Windows 7. But then instead of waiting for Windows 7 additional upgrades will soon be released for Vista and Server 2008.