FuseCal is a web app that does something so useful, yet so seemingly rare, that it's hard to believe it's both free and easy to use. The app, currently in alpha, lets you add iCal-based calendars (and a few other formats) to a master calendar, then choose whether all those events, just the ones you pick, or events filtered by keyword will be synced to Outlook, Apple iCal, Google Calendar, or another program. I've only had time to test the Google Calendar->FuseCal->Outlook setup, and it seems to work. Those with web sites can also publish their combined FuseCals on their site. FuseCal is free to use; a sign-up lets you keep your calendars in sync.