RedLisp is currently only an interpreter of a new dialect of Lisp. There are three implementations written in Java, C++ and Python. The C++ and Python implementations can be found in the SVN repo.

RedLisp isn't meant to replace any current Common Lisp implementation, because it isn't based on Common Lisp. There are quite a few differences between Common Lisp and RedLisp which are detailed in the LispDifferences wikipage.