Night Mission,
Melatonin never worked for me, at any of the dose I tried. All it did was to make me even more grumpy than usual. Then again, I seem to be quite resistant to "sleep aids" anyway, so my experience is probably not representative of most people's reaction.
I have, however, found an incredibly effective remedy for sleeplessness.
The remedy is boring lectures. No matter how alert and awake I am, I am off like a light within 10 minutes. I suggest you find a boring lecture and tape it, and play it to yourself just prior to going to bed. You may even be able to start a roaring business helping people to sleep.
Actually, even though it sounds like I'm taking the pee, I am not. I find that reading a very boring book also helps me to get to sleep much better than pharmaceuticals do, and it is a "safer, cleaner" way of helping myself to sleep.