How do you Choose and Hire a DJ Disc Jockey?

You can always find them in the yellow pages, friends of friends (at least one person you know must know of someone) ask around school, if there's a music store near you ( Sam Ash / Guitar Center ) they usually have a board where musicians put their business cards, you'll always find at least ONE dj there. If it is a superstar DJ you're interested in hiring, look up their myspace, usually you'll find there the company that manages them, and all their booking information will be right there.