Ask your teacher and coach, but having been through a sickening amount of auditions, I can pretty safely bet that those schools would much rather hear things from plays - as I said before, there's not really anything solid that I've come across from most musicals. There are fantastic monologues in WORKING by Studs Terkle, and I actually played the role in a production of it and used my monologue for auditions after that, but got sick of it. You might want to look into that if you want to do something from a musical. And I agree, stay far away from those monologue books. I would be happy to reccomend things - but i'm not quite certain, are you male or female?
"If you are going to do something, do it well. And leave something witchy."
-Charlie Manson