Ok, it seems some idiot spammer is using my domain to send out Citibank scam mail, I've been recieving a trickle of bounces so far, and one hateful message.
let me point out that I am not sending these, if you've recieved one of these and would like to report it, I suggest you use the fine Spamcop service, which is free to use for reporting (altough they really don't mind if you do subscribe, gets you a few nice additional features and supports the anti-spam movement).