It doesn't do anything for me but I've heard that drinking water with coconut oil can help if it's done before a meal, but I haven't tried it and don't know if it's true.
Drinking water before a meal also helps with the digestion of the food. According to the skinny rules by Bob Harper the first rule is: Drink a glass of water before every meal, no exceptions.
I drink all my water cold. Per studies done (though I have no reference currently) cold water has to be warmed up to maintain homeostasis in your body. The extra work on your body burns a small a out of calories. I figure I like it cold anyway, and overtime, that small amount could have an impact.
I always drink water or diet soda with every meal, it helps me enjoy the taste of the food better and seems to help digestion as well. For a while when I was at my highest weight I stopped doing this but then picked the habit back up when losing weight.