Microsoft has (much earlier itself), confirmed they are releasing PowerToys for Vista, which are an extremely useful collection of tweaks & utilities that greatly improved the Windows experience. While a Script Elevation PowerToys for Windows Vista has been already been released most Vista users are anxiously waiting for the TweakUI version for Vista.
The TweakUI for XP, is [by the way], not known to work on Vista. Though these are not officially supported, they are generated from internal projects of the Microsofts developers. They often add vital & useful features that didn't make it into Windows proper ! One of the most helpful for XP is/was the TweakUI. Its new version for for Vista is the one most Vista users are eagerly waiting for.
Reservations are being expressed that it may be classified as "Ultimate Extras". Hope not as the move would be construed as being unfair to the other Vista Users ! And while most were hoping for its release by this year-end, expect its release after the release of SP1...or at best along with it !
Source: The WinVista Club