Zepto.js – Tiny JS Framework For Mobile WebKit Browsers
It aims to help overcoming the most drudge work with a nice API so users can concentrate on getting things done.
Besides the most common functions that can be expected from a JS framework, it has support for touch events and detection of the environment.
Zepto.js is currently in early beta but still very promising.
Compatibility: iOS 4+, Android 2.2+, webOS 1.4.5+