A team from ooVoo were at Upling giving some demos of their multi-party video chat program. The app seemed to work extremely well, also not only is it on mobile handsets, the program is also availbale on desktops.
You can expect to get ooVoo on IOS as it was just launched on that platform and also on Android.
Right now you can connect up to 6 users in a single chat session (however you can only do 3 on the free version), they are planning on expanding to the number 12 soon.
While ooVoo seems to be doing well, the app is still only available to certain devices. At this time of writing, the Market page lists official support for the following devices: HTC EVO 3G & 4G, Samsung Epic, Samsung Galaxy S GT-i9000, Samsung Galaxy Tab 3.0, T-Mobile MyTouch 4G, Dell Streak 5, Nexus S and the Galaxy S 4G. ooVoo launched first on Android and says that it is their flagship platform. They say they’ve got expanded tablet support coming soon.