TransformJS is a jQuery plugin which exposes new CSS properties accessible through .css() and .animate() which you can use to apply and manage transformations to a jQuery element.

TransformJS uses feature detection to analyze the supported features of the browser it is running in and adapts accordingly and it maintains an in-memory matrix which it uses to apply the transforms.
The ability to use transforms without constructing huge stylesheets for x-browser compatability is nice.

Requirements: jQuery
Website: http://transformjs.strobeapp.com/
License: Free