A select group of customers, retailers and developers mostly, belonging to the Microsoft Technology Adoption program, will get to test drive Vista Service Pack 2 next week, but Microsoft hasn’t set a release for the rest of us.

The SP2 beta release, set for Wednesday October 29, has been announced by Mike Nash, corporate vice president for Windows product management, in a blog post on Friday.

Nash justified the lack of a definitive version release date by saying "The final release date for Windows Vista SP2 will be based on quality, so we'll track customer and partner feedback from the beta program before setting a final date for the release."

Vista SP2 will contain "previously released fixes focused on addressing specific reliability, performance, and compatibility issues," wrote Nash. But far from being just a collage of bug fixes, will contain a slew of new features such as Windows Search 4.0 “for faster and improved relevancy in searches”, The Bluetooth 2.1 feature pack that supports “the most recent specification for Bluetooth Technology”, Windows Connect Now for Wi-Fi configurations, native Blu-Ray recording for Windows, and an upgrade to the exFAT file system which supports UTC Timestamps in order to allow for correct file synchronization across time zones.

As a new feature, Microsoft has also adopted a “single serviceability model” so that SP2 will be packaged in a single release that covers both the Windows Vista client OS, as well as Windows Server 2008. Nash remarked that "This should also minimize deployment and testing complexity for our customers."

Despite the new features, Microsoft has encouraged users who are thinking about getting Vista to not wait for Service Pack 2.

"One question I know that you will ask is 'should I wait for SP2?'," Nash said. "The reality is that Windows Vista SP1 is a great platform that is both available on new Windows PCs and available as a free download for systems that are running the 'gold' release of Windows Vista. While we will recommend SP2 when it ships, your best bet today is Windows Vista SP1."

As for shipping the final version, Microsoft is keeping it under the lid. A company representative said that "it is too early to talk about SP2's final release date."

"As always, the final release date is based on quality and we will track customer and partner feedback from the beta program before setting a final date for distribution," the representative said.

The SP2 announcement comes ahead of the Professional Developer Conference next week, where Microsoft says that they are going to go into more detail about the next major OS release, Windows 7, as well as give developers a pre-beta version.

Update: according to ZDNet, this Microsoft blog says that we can expect the general release of SP2 somewhere in the first half of 2009.