iOS/Android/Symbian: Fring, one of our favourite mobile apps for VoIP calls, just released a new iPad app that supports four-way video calling between the iPad and non-iOS users. They also updated their iPhone, Android and Symbian versions to match.
Fring for iPad beats Facetime for multi-party video calling, and is the only iPad app that allows iPad users to talk to more than one other person without an Apple product. Fring allows you to drag names from your contacts list directly into the chat window to start a session with them. Drag in up to four friends and you'll be able to talk to them all at once, and they'll be able to chat with the group. Plus, since Fring supports iOS, Android, and Symbian devices, there are no limitations on who you can chat with.