Fring has just released a device-agnostic version of its iPhone application which allows Android -> iPhone video calls (PCs, too). Unfortunately, its become so popular that they had to block Skype access.

Fring said it themselves on their forums.

Hello everyone.

This is absolutely amazing. Since the release of our latest iPhone version yesterday we have seen a huge jump in fring video calling.

So, to free up some room for more fring-to-fring video calling, we are temporarily reducing support to Skype. Be patient, we'll have some more updates soon.

Interesting that the traffic would be so huge since those iPhone 4 users would have their own app; FaceTime. Of course, that's only good on wi-fi; Fring supports 3G.

Watch a video call between an iPhone and Android below: