The alarm clock across the room is a good way. I like to set mine to music, not the beeper, because the beeper is one of those sounds that makes me want to dive headfirst out the window every time I hear it.
I did the alarm clock across the room thing for a while, but when I got in college, my classes were late enough that I was usually waking up before alarm. Then, I got a job that required I get up at like 6am every morning. I NEEDED the job, so I couldn't be late. That was motivation enough to get me up every morning with the alarm. I do like hitting the snooze, so I'll set the alarm 21 minutes (7min snooze) early, so I can hit it a maximum of 3 times.
Any more, I can't sleep much later then 8-9am, regardless of how late I've been up or what I was doing the night before

. I guess I'm getting old
