I remember reading once about a guy who replied to these things agreeing to help with their plight, but also that he was wary and had heard of people being conned out of money, so could they prove their worth by sending a token amount (something like $1) to him.
Some did, some didn't. Needless to say he didn't continue assisting them.
I've just had a quick check on snopes, and it's doesn't appear to be there, so must be true.
