I think it does, yes, although I'm not sure.
What is definite, is that if you don't drink enough water, you put on weight - your body feels dehydrated, and so retains all the water you drink, making you put on water weight - which can make the difference in several pounds of weight loss.
As for actually making you lose more, I'm not sure. I suppose if you're drinking more, you tend to feel better/more energised all round, and therefore happier, and less likely to snack, and also if you drink lots you'll feel full and less likely to give into cravings.
Not sure about anything else though, sorry!