My friend Dirk sez:
The recently released iCal can publish calendars, either to your .mac account or to any DAV-enabled webserver. Apache 2.0 will work just fine out of the box; for apache 1.3 - you'll need to take a recent (newer than 10/9/02) snapshot or CVS release because apache was a bit too strict in its digest-authentication parsing. To publish to a site, follow the receipe at http://www.webweaving.org/ical/.