I've been using fring on my Nokia devices for years and just last week they announced two-way video calling for select Symbian devices. They are now following up this week with the announcement for the iPhone that gives iPhone and iPod touch owners the ability to VIEW video calls from callers over Skype or fring. With your WiFi-connected iPhone or iPod touch you can interact via voice to the person shown on your display, but you cannot make video calls from your iPhone or iPod touch. If Apple includes a front facing camera on the iPhone in the future then you will be able to make video calls as well.
I am evaluating a Nokia N97 mini and plan to try out the two-way fring video calling this week and now may test it with an iPhone or iPod touch to see what the experience is like. When I travel overseas I like to use Skype video calling with my family to stay in touch and show them some of the things I found during my travels.