This how-to over at Gearz.de will help you share your iCal calendar around even if you don't have a subscription to Apple's online MobileMe service (a very forgivable offense, especially since its expected replacement iCloud service is now just a week away). Unfortunately, the writeup is a little technical, as you'll need to actually configure your local web server to share out and broadcast the calendar to anyone who needs to read it. That means you'll need to do a little console typing and config file editing, but as long as you follow directions, it should work just fine.
A simpler solution might be to use an app like BusyCal to do the syncing for you, or even just use a service that's already in the cloud, like Google Calendar (which is what I actually do). But if you're already tied to iCal, either because you've got a calendar on there or just because you like the app, following those steps should help you get sharing to anyone up and running.