At last we have video calling via Skype – and it works well provided you have a reasonable 3G signal. Calls initiated from an iPhone 4 (with facing camera) to another iPhone 4 offer a similar experience to FaceTime, but with no need to set up both phones. To a fixed computer with camera the call is just like making a normal computer-to-computer Skype connection.
Just one observation which should be obvious: If your caller is to see your face in all its glory it's advisable to use a microphone.
PS: PocketLint says Skype video calls use 3.4MB of data per minute. So perhaps not such a good idea, particularly if you are roaming at £6 per MB. Must find a Starbucks.