It’s official: Skype has quietly rolled out an updated version of its iOS app that brings two-way video calling to the iPhone, iPad and iPod touch.

Version 3.0 of the Skype app, now available in the iTunes app store, can mak two-way Skype video calls between owners of the iPhone 4, iPhone 3GS and iPod touch 4th generation. iPad and iPod touch 3rd generation owners can receive video calls, but can’t send video back due to the lack of camera on these devices.

The new Skype app is also able to send and receive calls from its traditional desktop application. Thus, you can be video chatting with your sister while on the train. Skype 3.0 for iOS supports both portrait and landscape mode.

However, the killer feature may be that the app supports video calls over 3G. This is in stark contrast to Apple’s Facetime video chat protocol, which only works via Wi-Fi. Is AT&T about to let Apple do video calls over 3G, or will Skype overload an already-strained AT&T network?

This is a positive development for a company that has been embarrassed by a total collapse of its network that lasted over 24 hours. Skype explained that last week’s extended downtime was due to overloaded servers that sent out delayed messages that were improperly processed due to a bug in an older version of Skype for Windows.