USA Today, among others, is reporting that Gambian pouch rats (Cricetomys gambianus) have invaded the Florida Keys. A Florida scientist proudly (kidding) noted that this is the first documented naturalized population of these oversized rodents in the U.S. The ISW first reported on the pouch rats, as vectors of monkeypox, back in June 2003.
Update: Those aren't invasive species, those are land mine detectors! Maybe this will be a boon for the U.S. after all :-).