Rotate text ad on facebook page by IP?

Does anyone know how I could go about rotating a text ad on a facebook page by IP? For example: when someone from the UK visits the facebook page they will see a different text ad than if someone from the US visited the page.

While writing this I had the idea of using a script on a webpage and then using an iFrame. Could this work?

if your talking about FaceBook advertising that's not currently possible...

Though, I don't think that it's possible regardless on FB with perhaps the exception of FBML code.

I'm advertising on a fan page if that helps...