well now that 1-888-FACETIME is down I think some people might need this again... myself included!
I've had mine iP4 since launch, but I didn't feel a need to rush out and try to test it right away. My sister finally got her iP4 preorder a few days ago so 2 days ago I tried my very first facetime.... and there were problems...
I don't know if it was hers, mine, or both, but the more I think about it I think the problem is with her iPhone, but I need to test mine out to make sure.
PM me if you want to test out some facetime action!

Bonus points if you are a cute girl!!
If you care to know the facetime issue I was experiencing here it is. The front facing camera's both worked fine, but when we switched to the back cameras there were issues. When my sister switched her camera, I could see from her back cam, but her mini picture-in-a-picture didn't change, instead it froze on her face. And when I flipped mine, my PIAP changed, but she just would see my frozen face till I switched it back...

That's why I'm thinking hers with her iphone because mine always displayed correctly. But it's possible that mine just wasn't transmitting correctly I suppose as well. K well that's the story.