Jester - Easy JavaScript gesture recognition for iPhone and iPad.
Mobile-Web-based-Gesture-Recognition - Based on Dollar. Demo.
mootools-mobile - Wraps click handlers with touch and provides some custom events.
jquery.doubletap - Custom touch events for jQuery. Demo.
touch-layer - Custom events and gestures handler for touch enable mobile devices.
WKTouch - Hardware accelerated multi-touch drag, scale and rotate plugin for Mobile Webkit.