If you are iPhone 4 and iPhone 3GS user, you’ll like this app, Tango Video Calls make it possible make video call with you mate using 3G and Wi-Fi network. iOS 4 ofering facetime (video call) but you need Wi-Fi network. Using Tango you can use in 3G network too.

iPhone App - Tango Video Calls

Here is more detail features on Tango Video Calls

• Free video calling to your friends and family around the world, wherever you are
• Switch cameras and swap screens to show what is around you
• Move between video to audio and back to video
• Simple and easy to use
• Create an account in less than five seconds – New profile not required
• Call between iPhone and other smartphones on 3G and Wi-Fi
• Works on iPhone 3GS and iPhone 4 (but not the iPhone 3G, sorry!)
• Populates Tango Contacts automatically from existing phone contact list; we do not share your personal information, we simply use your phone number so your friends can Tango you
• Invite friends and others by e-mail or text

More details about Tango Video Calls you can get it here