who was the message from?  What did you do to win that money?  Did you enter a contest?  

Its probably a scam.  They'll ask you to pay taxes in advance, keep that money and never send you the prize.  Or they'll ask for your credit card number "for identification" and use the card to buy stuff for themselves.  Or they'll ask for your bank account number so they can "deposit the proze" and empty the account instead.