Being a regular gym-goer, I once took a supplement known as "ZMA", a blend of zinc, magnesium and Vitamin B6. You take them before bed on an empty stomach, supposed to increase testosterone levels or whathaveyou. Me and a friend tried them at the same time. About two weeks later, we were in the gym and my friend tells me about an extremely vivid and distubing dream that he'd had the night before, and that he has been having crazy dreams all week. He was surprised to learn that I'd been experiencing exactly the same thing, and had very intense and vivid dreams as well, and continued to do so whilst i was taking the supplements. I took them again about a year later and exactly the same thing happened. I looked up on the net and was delighted to see that many other people also report the same thing.
I can't really say whether they help with weight training or not, but to me, it doesn't matter, they are worth their weight in gold because I tell you what, you feel like you've slept for days the next day, they are an excellent sleep aid, but have the added bonus of inducing crazy crazy dreams - they are cheap as well and it's just vitamins so nothing artificial to worry about - I absolutely recommend giving them a try!
Methtical