

Screenshot courtesy of Engadget
Google Announces Android Video And Voice Chat, Along With A Twitter Puzzle Challenge
Video calls works over both WiFi and 3G. However, T-Mobile began blocking video chat over 3G on their network this week.
Confirmed: T-Mobile blocking GTalk video chat over 3G on Nexus S (Engadget)
Engadget confirmed that Gtalk video chat still works over 3G on Sprint’s Nexus S. The feature is only allowed when connected to a WiFi network.
AT&T previously blocked even voice-only calls over Skype for iPhone users on their network. It too was a WiFi-only service for a period of time. This restriction was lifted just a year ago (May 2010).
