It's part-time, yes, but reading this thread leads me to believe that sometimes they make you work up to 40 hours during busy times. Also, the 20 hours a week isn't flexible (e.g. you sit down when you're not busy and crank them out). They'll give you a schedule for say, Tuesdays, Thursdays and Saturdays between certain hours (5:00am-11:30pm CST) and if you have a class during those hours you're SOL. The hours you work are set by Apple and are good for 90 days, and then they rotate them.
Obviously I don't work there, but from what I can tell it's not for those who need flexible scheduling. My guess is during your interview you should bring up that you're a full-time on campus student at the beginning and see what they say.
Again, thank you!
A schedule, such as the one you included as an example, is exactly what I was expecting (and hoping for). I will bring it up during the interview because I would hate for them to hire me only to later find out that I'm of little use to them.