Just like if we have a plane to catch early morning, we jump up at the first bell of the alarm, because we know we just can't miss the plane.
Fajr is much much more important. Before you sleep, recite suratul Ikhlas 3 times (Qulhu wallahu Ahad..) then suratul Falaq and Naas. Also Ayatul khursi, if you don't know it you can listen to it here: http://www.youtube.com/watch?v=z8ARFtBLza4 . Listen to it often and you will byheart it InshaAllah.
Go for it bro, I too had this difficulty, but now alhamdulillah I m punctual. Now make the sincere intention that you WILL wake up every day for Fajr, not for you, not for me, but for ALLAH the Almighty. Come on bro you can do it.