By far the best Clojure web framework I have yet encountered is Compojure: http://github.com/weavejester/compojure/tree/master
It's small but powerful, and has beautifully elegant syntax. (It uses Jetty under the hood, but it hides the Servlet API from you unless you want it, which won't be often). Go look at the README at that URL, then download a snapshot and start playing.
