I get those occasionally on the fax machine. My advice to you is to do exactly what I do...file it away in File 13, the circular file, wastebasket, whatever you call it. It's a scam...they're hoping that your greed will override your common sense and cause you to give them access to your checking account...which they will promptly empty.
This is one of the oldest scams in the book. Stear clear my friend. http://www.snopes.com/inboxer/scams/nigeria.asp man I can't believe I beat martin to this
Here is a funny story of some guys that turned the tables on them and actually scammed the scammers. http://news.bbc.co.uk/2/hi/africa/3887493.stm