I was planning to get up early this morning <early being six a.m.> because tomorrow I have to *be to* work at five a.m.! But I slept in until, well, NOW! (Which is seven a.m.)
There is also another method (which I am not certain is available everywhere, but...) called 976-WAKE. It's a 24-7 wake-up call service. You call the number, put in your number and time/day to get a call, and an automated voice calls you for a wake-up call.
When I absolutely, positively have to get up, I use this service.