Getting up way to early to go to the gym is not really that hard physically, the biggest obstacle to overcome is your rationalization reflex. Your brain really wants you to go back to sleep, so you can easily think of a million reasons why you should lay back down.
Luckily, for me, I have been able to convince myself yet again that I should go. The deciding factor is usually something along the lines of, "Well I am already standing. If I just start putting on my gym clothes the momentum will get me there, and I can check off the little box on my weight tracking spreadsheet to say I went to the gym again."
So far this tact has generally worked for me since November 17, 2001 ... to the tune of about 85 pounds, and putting me in pretty good shape.