Apple says that Boot Camp 1.2 beta contains several updates and is intended for all new and previous Boot Camp beta users.
Boot Camp 1.2 beta includes:
Support for Windows Vista (32-bit)
Updated drivers, including but not limited to trackpad, AppleTime (synch), audio, graphics, modem, iSight camera
Support the Apple Remote (works with iTunes and Windows Media Player)
A Windows system tray icon for easy access to Boot Camp information and actions
Improved keyboard support for Korean, Chinese, Swedish, Danish, Norwegian, Finnish, Russian, and French Canadian
Improved Windows driver installation experience
Updated documentation and Boot Camp on-line help in Windows
Apple Software Update (for Windows XP and Vista)
Updating to Boot Camp 1.2 beta
If you previously installed Boot Camp beta, you can easily update to Boot Camp 1.2 beta. You don't need to partition your hard drive again (unless you want to change its size) or reinstall your Macintosh and Windows software or documents, but it's very important to update the Boot Camp Assistant software, create a new Mac Drivers CD and install the updated software it contains onto Windows. Complete instructions are provided in the Installation and Setup Guide included with the Boot Camp 1.2 beta software.