We are using Facebook Connect, and frankly part of the motivation in building Pixza was the lack of any quality multi-player game on Facebook. Those farming, fishing and mobbing types of games which claim to be "multi-player" are in fact asynchronous games, while in Pixza you play with your team mates in real time, synchronously. And did we mention we don't use Adobe Flash? Pixza works on just HTTP and COMET techniques and so with a few minor UI tweaks, Pixza should work on the iPad and iPhone too.
Game link: http://pixza.com
We have also made a screen capture of an actual game here (speeded up): http://www.youtube.com/watch?v=sKMDitT_uwc&NR=1
(Clickable links in the comments)
We are basically a team of two college students from India, who worked on this part time for the past year or so, and we have been beta testing the game with all our friends. We are now ready to bootstrap and publicise it, and we want your views on Pixza.
Thanks a lot!