I have a theraltake cooler for mine. It's a couple of years old (don't recall the model number) but it works. It has a 12CM (120MM) fan in the middle that blows cool air under the laptop. I have been able to overclock my CPU by 15% & even overclock my graphics card without any overheating issues.
On a seperate but related note, my old acer couldn't run WoW for more than an hour without overheating unless I had it on a cooler. When it was on the cooler it would run for hours without so much as a hiccup, but take it off the cooler & it would overheat in a hury. My brother has that old Acer not & he still has the same overheating issue when putting it under any stress. Put it on a cooler though & it runs fine.
Long story short, yes laptop coolers work. Some better than others, but I think that you will find that all of them aid cooling somewhat.