Here is a very cool app for smart phones! Tango enables mobile phone user to have video calls and can be used over all smart phones. That is right an Iphone user can conduct a video call with an Android user over 3G! The calls are of good quality and you can see who you are talking to!! If you prefer Skype they have a Skype app and a SKype WIFI app! Too cool!
Tango lets you use two cameras to show yourself and your surroundings. It also works well on phones with only a rear camera, such as iPhone 3GS (yes people still use the 3GS), iPad or Android, briefly show somebody something around...