CLPython is an implementation of Python in Common Lisp. At http://common-lisp.net/project/clpython you can read more, download the source (released under LLGPL), and subscribe to the "develop" or "announce" mailing list.
For now the major functionality offered is a read-eval-print loop (in Python terms an "interpreter") which understands a large part of the Python language. And currently only Allegro CL 8.0 is supported. But hey, it's a start. Portable CL, speed improvements, full Python language (and modules) support, and Lisp-Python bridging are the next targets.