After reading my Airtunes hint, several people have asked me to post a script to restart an AirPort Base Station ... so here it is. The script assumes you can at least see the Base Station in AirPort Utility, which is not always the case so YMMV. You can use the launchd utility or Cronnix if you prefer to schedule it. If you have a shell script for this, please share as I think that would be a more elegant solution.
Meanwhile, here's the AppleScript:
Mac OS X Hints
http://hints.macworld.com/article.php?story=20071228144426216