When I can't sleep because my brain won't stop, I tune to talk radio and hit the sleep timer on the clock radio. I know this might sound like too simple a solution but it's worked for MANY people I've suggested it to and for me over 90% of the time. Your mind gets engulfed in the conversation of others and not the ones in your own head!

I also think the melatonin might be a good suggestion. I just looked it up because I remember someone on another board posting that it is not advised for MS patients but the first hits that were returned all cited at least one study that concluded that nocturnal melatonin levels are reduced in a subgroup of patients with multiple sclerosis. Interesting!