Saurik has updated WinterBoard to be compatible with iOS 5.

WinterBoard provides hooks that let graphics artists safely and simply theme almost anything in Apple’s OS, including third party software downloaded from App Store. Multiple theme packages can be installed at once using the configuration interface: simply drag themes into a priority order.

WinterBoard was designed to accept SummerBoard themes without modification but is much more powerful than its predecessor and can theme almost any graphic on the system. You can even easily modify .artwork files without having to hack their contents, all from the safety of your theme folder.

What’s New in 0.9.3901
? 5.0: CSS Text Style Crash Bugs
? 5.0: Cache Delete (Thanks iHaz3!)
? 5.0: Clear SMS (Thanks Sakurina!)
? 4+5: IconAlpha Fix (Thanks NickF!)
? 4+5: Dock Names (Thanks Surenix!)
? @2x: WB Icon (Thanks Surenix!)
? @2x: Massive @2x Reimplement
? 4.0: Remove SummerBoard Grey
? Lower-Level Hooks (More Images)
? Remove Outdated Demo Themes
? Rare _UIImageWithName(nil) Bug

You can download WinterBoard from Saurik’s Cydia repository.