Whichever email you have on file, that's the one they'll send it to.
I think you have to wait until Mtbaker checks in and sees the results. He just happened to be around when I won, so I got mine very shortly after I won.
Still haven't spent it, but I have it!
Winning is fun, isn't it?
Btw...you can go into the shopping site and check your account information to see which email you used.