TechARP predicted last month that RC-Escrow build of SP2 for Windows Vista and Windows Server 2008 will be released between the dates Jan 26-30 and the RC build between the dates Feb 16-20. The RC Escrow build of SP2 was sent to testers at the end of January and the rumor is that now Microsoft has released the RC build of SP2 to Microsoft Connect testers exactly between the dates predicted by TechARP.
Ars reports that RC build is available for download as a standalone installer package or via Windows Update or as a slipstreamed download which includes 691 individual hotfixes. Public beta of SP2 was released in December 2008 and the final release is expected to happen around April or May according to TechARP.
Windows 7 also appears to be moving towards the release candidate build at the end of February, which raises a serious discussion over whether users would still stay on Vista or jump to Windows 7. Not to forget that Windows 7 is also rumored to hit RTM in August.