Just thought I'd point out a great presentation about the "new" 9.3 geoprocessing (gp) python module from ESRI.
Ghislain Prince and Elizabeth Flanary do a great job of introduction by examples. The latest gp module is much more pythonic and these examples show how to leverage that to its full advantage. If you try to do this with older gp versions, the code would make most pythonistas cringe. This latest version returns objects and lists, use real booleans, and uses true objects instead of funky string parameters. Basic OO stuff for most python libraries but a big improvement for gp.
Here's the powerpoint presentation. Thanks to Jamey Rosen for the tip!