there've been many times i've wanted to, with tongue only half-firmly-planted-in-cheek, suggest that all the insomniacs move to a state (or country) where marijuana's legal (medically or decriminalised). i live in los angeles.
yes, it works. it's great. just get the right kind. here in california, a good pharmacy with a knowledgeable staff would be able to show you a few strains. but broadly speaking you'll be looking at a pure indica or even a hybrid with an indica-dominant strain. some of the co-ops also sell edibles like muffins, cupcakes, brownies, cookies, tinctures. people report a deeper, more body-centric effect with those, which is supposed to be even stronger at helping you sleep.
the downside is it can get pricey. good strains can cost $80 for 1/8 oz but the proliferation of co-ops and competition means you can get good ones for $60 and a few places might sell you something for $40 or $45 (maybe in the valley, these are la prices). it hasn't been federalised so theoretically you can still be stopped by law enforcement (though i hardly hear about that happening anymore and it's never anything heavy if you have less than 1 oz) and you certainly can't air travel with it, and your card won't get you out of trouble if you take it with you to a state where it isn't legalised, yada yada.
you could also try the marinol pills, which i understand are extremely strong.
good luck!