I was just browsing the web and stumbled accross this. Whoohoo, Vista and 2008 SP2 Customer Preview Program!.

Wait… what?! Vista and 2008 SP2 BETA?
That’s right! A single service pack that covers both Client and Server!
This is actually pretty nice! This reduces the management of service packs for both server and client. Just service packs
So what’s actually in there?

Well… seeing as after you installed a fresh Vista SP1 machine you almost get crushed by updates. Here’s a list of hotfixes included in service pack.
Other then that there are a few new features:

• Support for new types of Hardware and emerging standards, including Bluetooth 2.1, the ability to natively record data on Blu-Ray media, support for ICCD/CCID smart cards, and support for the new VIA 64-bit CPU
• Wi-Fi setup and maintenance is simplified with the addition of Windows Connect Now (WCN)
• The ex-FAT file system is enabled, supporting UTC timestamps to ensure correct file synchronization across time zones
• Windows Search 4.0 is included, which provides users faster and more relevant results. Windows Search 4.0 also allows Group Policy integration, which provides administrative control over search parameters
• End users should also experience improvements in resume performance when a Wi-Fi connection is no longer available

Get your copy here!

EDIT:

You can also get the SP2 update through Windows Update. Use the script below to enable the update:

reg delete HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\VistaSP2 /f
reg delete HKEY_LOCAL_MACHINE\SOFTWARE\Wow6432Node\Microsoft\Windows\CurrentVersion\WindowsUpdate\VistaSP2 /f
reg add HKEY_LOCAL_MACHINE\SOFTWARE\Microsoft\Windows\CurrentVersion\WindowsUpdate\VistaSP2 /v Beta1 /t REG_SZ /d 93F7D954-DF91-22E6-99AB-4D8AF54E813A /f