Attire: You should be respectably presentable and professional. This doesn't necessarily mean a tux if you're a guy, or a $500 dress if you're a girl, but don't wear anything that resembles street clothes. Shoes should be comfortable and not prone to making annoying squeaking noises on a stage floor.
Bringing music: Scores are generally not needed for the faculty auditioning you, unless they request it. If playing an unknown work, make sure you give them the option of observing an original score while you play. I'd bring the scores just in case.
Scales: Again, usually not requested at most college auditions, but if they do, be ready to play them!
Chances are that for most pieces you play, they will stop you before finishing the piece, so spend more time practicing the first 3/4 of the pieces...
Where are you auditioning?
Topic: College Auditions