a friend of mine is currently recovering from a severe case of insomnia he's had for about 2 years now, he's recently had his first "full" night of sleep in years. he spend 2 years sleeping a maximum of 1,5 hours a night (if he was lucky)
he actually went to the hospital, had a full neurological examination, prescription medication and a "sleep-psychologist". but the thing that probably helped him the most was setting himself a steady routine, get into bed at 23:30, and only get back out at 7:30.....
just trying to sleep, and getting some rest.
that said, since going to college, i've managed to screw up my day-night rythm pretty nicely myself.... (spend a time at school from 10-16, work from 17-23 and painting till 4, leaving myself some 4 hours s7to sleep each and every day)
something that helps me get to sleep is tv, especialy the discovery channel and NGC, channels with good narrative description.... something you don't have to necessarily watch, but is interresting nonetheless...
hope this helps