I know someone is going to tell you studentdocket but its expensive and from my experience from the trial not worth it. but it has a 15 day trial you should check it out for yourself.
Student docket is on sale for $10 at the crackberry app store, and you can get the crackberry back to school sale for additional savings. I love it, since it allows me to keep track of teachers/classes separate from my personal tasks.
I would like to see an app that you can set each class to a specific column and set the time of each class then you can click to add assignments to it. Kind of like a calendar-type app but for you classes. Maybe do a short vibrate when class starts/ends. Something designed around your classes