Tungle looks fun.
Tungle is a free, effective and simple meeting coordinator.
Share your availability
View the availability of friends, colleagues or business associates before sending them a meeting invitation.
Coordinate meetings with anyone
Create Tungle Spaces – temporary web sites for coordinating meetings with anyone, including people who don’t have Tungle.
Use your existing calendar
Get started in seconds, using your existing calendar (e.g. Outlook, Lotus Notes and Google Calendar) across firewalls and organizations.
What I find really attractive about Tungle is that you can use your existing calendar. At work we use Meeting Maker to organize meetings but it doesn’t connect to your existing calendar application (it does with an expensive plugin!).
Not that I’m a Mac user, but there doesn’t appear to be support for iCalendar, which seems a shame/short sighted.
I wish I had an excuse to play around with Tungle now.