As was reported from overseas last week, devices running iOS 4.1 repeating alarms in the Clock.app will not work correctly. It is also affecting various applications which use the alarm features. You have to disable the repeat feature and then after today (12:00 am Monday) set your alarms to repeat. This should fix the problem.
Apple has anknowledge the problem and an update is in the works. Please visit support document TS3542 for more information.