I have tried that before and found it doesn't work for me unless I have something really forcing me to get up early (classes did the job, work does not). I may just not be viewing my incentive to get up early correctly. On the other hand, my brain is bad at managing motivation in the early morning, especially if I didn't get enough sleep. It's a lot easier to see the importance in "go to sleep now" than in "wake up now", because the former happens when I'm already awake.

Also, I can (and regularly do) stay up well past the point that I'm tired enough to go to sleep, but not so tired that I want to go to sleep. The difference is usually 2-3 hours, and the net effect is that my sleep schedule creeps forward over time to the extent that, if there's nothing regulating it, I cycle through the full 24 hour period in about two weeks.