Fring has released an iPad optimized version of their app that can do 4-way video calling. Now you can talk to 4 people at once and because the screen is cut in 4 you can see everyone.
You can make the video calls over 3G as well as WiFi and as an added bonus, Fring is a multi platform app. You can use it to talk and video chat with your friends even if they have an Android device.