From the "Guido must be happy" files:

Python 3.0 is now officially out - breaking compatability (in many respects) with currently deployed Python 2.x series. Don't worry it's not all lost for existing Python users, though the official Python release does sound dire.

Python 3.0 (a.k.a. "Python 3000" or "Py3k") is a new version of the language that is incompatible with the 2.x line of releases. The language is mostly the same, but many details, especially how built-in objects like dictionaries and strings work, have changed considerably, and a lot of deprecated features have finally been removed. Also, the standard library has been reorganized in a few prominent places.

You see in October Python 2.6 was released, and it is an effort to bridge the gap between the 2.x and 3.x versions of Python. When I spoke with Python developers back in October the expectation was that many developers would stick with the 2.x line for awhile and not immediately jump to 3.x when available.

"We are not expecting or encouraging developers to migrate to Python 3 immediately, and the Python 2.x line will continue to be supported and improved for years to come," David Goodger, an officer of the Python Software Foundation, told InternetNews.com ."Python 2.6 is an upgrade intended for most developers of production systems. Python 3.0 is for those who like to live on the bleeding edge."