From Python.org:
We are pleased to announce the release of Python 2.3c1 on July 18, 2003. This is a release candidate. If no serious problems are found in the next week, we will release this code as Python 2.3 final. We expect the final release to occur by the end of the month at the latest. The roadmap for the Python 2.3 release is PEP 283.
You can download it as a Windows binary, or in a tarball for *nixen. This release also incorporates a bunch of the idlefork improvements in the interactive interpreter.
Also check out the highlights for the 2.3 series.