[slashdot]

You should check out http://tungle.me, it's a much more complete product (calendar syncing, nicer UI)

[brianlash]

I don't know. How "complete" do you need a one-off solution like this?

I'd have no qualms sending my friends or a work group to this site to solve a scheduling problem in a hurry.

[bravura]

http://doodle.com is yet another competitor.

[caryme]

Doodle is in fairly widespread use at my school