I actually got this signature went I MEET HER at one of her concerts! But a friend of mine did used the address below and got a signed photo back. She sent a pic of Selena singing in concert but didn't get it back. Instead she got a head shot. So I'm guessing send something she likes and you'll be getting sometime:
Selena Gomez
Hollywood Records, Inc.
500 S Buena Vista Street
Burbank, CA 91521-6369
USA
I don't know what everyone's talking about, that outfit doesn't make you look like a hooker.