My friend had this happen to him once, someone used his email to create an account... I busted into the thing, changed the password, sent this unknown person's friends nasty messages, messed around some more, and then deleted it at my friend's request as he had no want for said account to be open. I got told off by this idiot's friends for "hacking his facebook," I simply told them to advise their guy that if he did not wish for "his" accounts to be messed with that perhaps he should use his own email instead of someone else's. The whole thing was rather amusing.
As a side note, I pity whomever has
biteme@(whatever).com as an email... I'm sure that account is damn near unusable with all the spam they get from everyone using it for one thing or another.