ClojureMode is a major mode that provides font-lock, indentation, and functions for communication with subprocesses for Clojure.
It’s more useful if used together with nREPL.el to interact with subprocesses. See this guide for details on setting up Emacs for Clojure development.
Download it here: http://github.com/technomancy/clojure-mode
Please note that http://github.com/jochu/clojure-mode is outdated and not actively developed although it is found on many websites.