* no phones during classes or during breaks (with the exception of lunch break, I think)
* phone can be allowed by teachers for a particular class and purpose
* if a student uses a phone while it's not allowed, the phone will be confiscated until the end of the school day
* (there might be a more severe rule for repeat offenders)
IMHO this strikes a pretty good balance between allowing phones for coordinating transit to school and back home, and no distraction in the class room.