Halloween is just around the corner, and Selena Gomez has already selected her costume for the holiday festivities. The “Wizards of Waverly Place” called in to Ryan Seacrest's KIIS FM radio show to announce that she’ll be going as Katy Perry. Selena explained, "I went to Katy's Perry's concert last night so I got my costume idea. She wore this really pretty pink dress with sparkly shoes and my friend was wearing a pink wig. It's piecing together I'm pretty excited!" As for her recent suggestion to Justin Bieber to cut his hair, Selena clarified, "Whenever I hang out with him he is do...