Publish iCal calendars without .Mac: "iCal publishing requires WebDAV. But now there's a way.
Box.net offers free 1GB accounts, and their servers run WebDAV. So here's what you need to do, in a nutshell:
Set up your box.net subscription (easy and fast!).
In iCal, publish your calendar (Calendar -> Publish) to https://www.box.net/dav, using your box.net account name (email) and password.
Subscribe to the calendar in iCal (Calendar -> Subscribe) at http://www.box.net/dav/Your_Calendar.ics. NOTE: Do not use https here.That's it!