Skype – free IM & video calls
The most obvious for a bevy of reasons. It’s best to use Skype over WiFi, as it won’t drain your data.
Tango – Free Video Call & Chat
Sure, it takes two to tango. With this app, though, you can video message a group of people with ease.
ooVoo Video Call, Text & Voice
This app really pushes the 6-way video calls, which is intense. However, it’s very useful for situations where you absolutely need to share big news with multiple people.
There are versions of Qik for pretty much every service provider, and my favorite feature is the live video streaming. As you add more and more contacts, you get a steam of videos of friends sharing moments in real-time.
Qik Video is a good for sharing videos, but Ustream is the best for watching live videos.