welcome to the wonderful world of the nigerian love letter. it's a scam that can cost you anywhere from nothing to your life savings, depending on how trusting you are in someone you've never met.
Here is a website of people who fight back against these scammers the only way they can; by humiliating and berating them:
http://www.419eater.com/ I wouldn't recommend doing this, but perhaps you could send this yahoo contact their way, I'm sure they would love to help this guy cash his check
