I'm afraid I need to -1 on this. If I'm developing a new package, I try and avoid putting a release on PyPI until I have something stable, but I'll often put up an entry on PyPI explaining where the code is being developed.
Working on a project for a year only to find that someone else has stolen your package name on PyPI (playing devils advocate here, lets say they saw the development of GitHub and knew a release was brewing, etc) and having to go through and rename everything seems unfairly painful...