From Prime Timetable:
Prime Timetable is a unique online school timetable software that helps teachers to create school timetables easily and efficiently. Create a school timetable easily from any computer with Internet connection (both online and offline timetabling are supported) and share timetable with teachers, students, parents and others. Prime Timetable is the world's first completely web based school timetable software that works natively in all browsers on Macintosh (Mac OS X) and Windows, but you can also easily view school timetables via iPhone, iPad, Android, Nokia, Windows Phone or any other mobile phone, smartphone or tablet via Mobile Timetable. With such innovative features as 3D school timetable, extra views and more, you will enjoy timetabling more.