IronPython, an implementation of Python on the .NET runtime, is fast approaching a 1.0 release. Jeff Cogswell has a longish introduction to what IronPython is and what it can do. One thing I can't figure out though, is where IronPython diverges from CPython.
Bonus link: A March Q&A with Guido von Rossum, the creator of Python. He doesn't say much about what he's doing at Google, but drops some hints about Python 3000.
Hat tip to J. Scott Miller.