The iPhone 4 may have re-popularised the idea of mobile video calls, with its WiFi-only FaceTime system, but its taken Fring to bring true 3G video calling to the smartphone (and make it cross-platform compatible too). The company's newest release - available for Android, Series 60 and iOS - now supports video calls over 3G networks, as well as the usual VoIP and text chat.
If you're an iOS4 user you'll be pleased to hear there's baked-in support for Apple's multitasking system, so Fring stays call-aware in the background and will alert you to new messages or incoming calls. They've also tried to make the app the single place you go to check all your social networking updates, with Twitter and Facebook integration too.
Video demo after the cut
We tried to use Fring on the Galaxy S a few weeks back but found the old version of the app would only recognize the rear-facing camera rather than the front-facing webcam. Until Apple - or, more likely, their wary carrier partners - open up FaceTime to 3G use, Fring may be the best way to video chat while mobile; that is, assuming you ever wanted to in the first place.