RichFaces

JBoss RichFaces is a rich component library for JSF built on top of Ajax4jsf, an advanced framework for easily integrating AJAX capabilities into business application development. The RichFaces components come ready to use out-of-the-box, so developers can immediately save time in taking advantage of component features to create Web applications that provide a greatly improved user experience more reliably and more quickly. RichFaces also includes strong support for the skinnability of JSF applications.

http://labs.jboss.com/jbossrichfaces/