http://www.mail-archive.com/pypy-dev@codespeak.net/msg03946....
That post also mentions Pyjamas, a port of Google Web Toolkit which compiles Python instead of Java: http://pyjs.org/
http://www.metapaw.co.uk/projects/metapaw-dip/
I really, really want to do Python client-side (or rather compile Python to Javascript). Javascript is just so painful for me. Being able to test Python code as Python would be the major reason.
http://www.mail-archive.com/pypy-dev@codespeak.net/msg03946....
That post also mentions Pyjamas, a port of Google Web Toolkit which compiles Python instead of Java: http://pyjs.org/