Microsoft released last week to testers what is believed to be the release candidate for Vista's second service pack, which means they are right on schedule to make a public launch of the pack by early April.
The Vista Service Pack 2 started its testing phase last October and is without a doubt the last big update it will push to the OS before it releases Windows 7 later this year. The service pack will update both Vista and Windows Server 2008, and will require SP1 as a prerequisite to avoid making it cumulative and therefore much larger in size.
Besides bundling all post-SP1 updates and security fixes, SP2 is expected to add a number of features including: Windows Search 4.0, Bluetooth 2.1 support, Blu-ray media recording, Via 64-bit CPU support, Windows Connect Now for Wi-Fi connections, improved power management policy, and improved audio and video performance for streaming high-definition content, among others.