Okay, back on topic for a minute.
Replacement parts for these are hard to get and stupidly expensive at the moment, although I suspect they'll get much cheaper over the next few months (iOS 7 means no one can sell nicked iPhones anymore, so eBay will be flooded with "parts").
It can be stripped and a repair attempted, or Apple will do an Out Of Warranty exchange (give you a new phone) for £209. The warranty on this is 90days or until the one on yours runs out, whichever is longer (the one on yours, 100%).
Expensive I know, but unless it's cleaned properly any other way might be false economy.