Natural remedies: Excercise! Smoking pot was never as easy as it is now, because I took fitness class 3 times a week, and my weekend job requires a bit of moving around too. As long as you're doing more than sitting in class or sitting in front of your computer, thats enough excercise. Since the leftover THC is stored in your fat cells (thats how pot drug tests work!), it makes perfect sense to burn off that fat!

Sunlight! Take a half hour walk, go play some sports, read a book in the sun, anything but do it in the sun. It may be a bit cold right now, but if you can grab a winter coat and rake some leaves, you will make it easier for your body to replenish its melatonin at night (pot purges melatonin in your brain), which brings me to:

Sunset! If you can, watch the sunset. Sunset triggers your body to produce melatonin, and will make the evening without pot much easier.

Unnatural but helpful: Melatonin sleeping pills, if you can find them. My local Bulk Barn had them, most health food stores do too. They give you the same sleepy effect that pot does , without the high, helping you with the insomnia during the withdrawal. Melatonin is great if you picked the wrong day to run out of/quit weed, and really need to get to sleep. They give you REAL and R.E.M. sleep, unlike traditional sleeping pills, and they are less addictive.

I've done alot of research on all of these, but I don't feel like finding the resources right now. If you want, look up: DHEA (sunlight hormone), Melatonin (sleep hormone).