Microsoft has given its MSDN and TechNet subscribers access to the beta of Service Pack 2 for Vista and Windows Server 2008 and will make the software available to the general public in two days.

The beta includes all the hot fixes that have been released since SP1, which shipped in March. Also included are some new features for corporate users including full integration of Hyper-V into Windows Server 2008.

Microsoft shipped a beta of SP2 in October to a small group of users in its Technology Adoption Program. This week, Microsoft is opening up the testing and plans to release the software next year.

"We are tracking to ship Windows Vista SP2 in the first half of 2009," Mike Nash, corporate vice president for Windows product management, announced on the Vista Team blog. The release will come ahead of

Windows 7, which some speculate could ship by the end of 2009. Microsoft's official timeframe is January 2010. The Hyper-V integration includes one free guest license for users of Windows Server 2008 Standard, four free licenses for users of the Enterprise version and an unlimited number of licenses for the Data Centre version.

SP2 also includes the ability to configure power management policies via Group Policy, and improved backward compatibility for older Terminal Server license keys that are only 512 bytes.

Other improvements include the addition of Windows Search 4.0; the Bluetooth 2.1 Feature Pack that supports the most recent specification for Bluetooth technology; the ability to record data on to Blu-Ray media natively in Windows Vista; the inclusion of Windows Connect Now (WCN) to simplify Wi-Fi configuration; and the enablement of the exFAT file system to support UTC timestamps, which allows correct file synchronisation across time zones.

Users must have SP1 installed before installing SP2 and need to have loaded the update to the Windows servicing stack.