Do I have to register my iClicker for each individual class?
No. You only need to register once and your registration information will apply to all of the classes for which you are using iClicker (provided you have voted with your remote in each class). Exception: the one point of possible confusion is if your instructors are using different student IDs to record your grades. Make sure you consult with your professors about the proper student ID (likely your CSU eName) required when you register online.