Peter, as the others haven't spelled it out (I think), this is a common trick where they hack into someone's email account, and send the same email to everyone in that person's address book.
It always says that they are stuck, and need money via something like Western Union.
Not really surprisingly, I think this catches out a lot of people who just want to help out, but it is definitely a scam.
Hey, could you help me out though? I am stuck here in Sydney and I urgently need a way to go somewhere there is wind! Somewhere warm would be nice, but I would cope if it wasn't. Can you wire me a couple of grand until pay day?