David Schumacher has released version 7.2 of ATP Autosite. ATP is a "site automation script" that automates many tasks needed to update a daily (or less frequent) webcomic site.
ATP allows for archive navigation through back/next links, monthly calendar links, and a drop-down menu. Version 7.2 adds new features such as providing for a comic "title" and allowing for daily text with the comic to be archived.
2010 Update: David site stopped updating around 2003 and he pulled all versions of ATP from the site. Not sure if there's another source for ATP available. The only major site I'm aware of still using ATP is John Allison's Scary Go Round.