Hi Micheal,
I have/had insomnia problems for just over 8 months, so I understand how vital sleep is. You might get better advice if you specify the type of insomnia you are experiencing, and what originates the problem. It seems like your problem is long-term and persistent, if you don't know why you are having trouble sleeping I suggest your visit a sleep lab/clinic (were they can measure your brain waves using electrodes, and then they can figure out which cycle is being interrupted). Once you know what the problem is it will be easier to treat. If you do know why you aren't sleeping (side of effect of injury/anxiety?) I suggest you try and fix that problem which will in turn fix your insomnia.
Here are some ideas:
Naturally: You can try the melatonin, your body produces melatonin naturally.. the chemical gradually increases in your body during the day making you feel tired. So if your body isn't producing enough of it, then you won't feel tired. This is available by perscription and in some health shops.. look around. There are none to very little side effects of the drug. It works great for some people..
You can also try to feel more relaxed at night by meditating, eating certain foods (bananas), or listening to soothing music. You can also try exercising early in the day.. to take away your energy.
Chemically: Some anti-depressent/anti-anxiety drugs are good for sleep at low dosages.. Elavil helped me a lot for a few months at 10mg. However what works for one might not work for another, but it is worth trying.. makes you feel really drowsy. Also opiates are sedatives and will bring on sleep, I'm particularly found of codeine's effects for sleep. I don't have much experience with other opiates just yet, so I can't compare -- although I'd imagine any others would work too.
I hope some of this information proves useful.