A while back I bought this Targus laptop cooling fan for my husband because he was stuck home in bed recovering from surgery and he was using the laptop pretty much all the time and it would seem to get extremely hot underneath where he had it resting on his lap.
When I first got it home, it seemed very cheap and flimsy and it's light as a feather. Once we got it plugged in though, it worked great. It helps prevent the laptop overheating by using a two-fan cooling system that pulls heat away from the laptop and keeps the CPU from getting too hot. You power it by pluging the provided USB cord into your computer and then turn the fans on with the on/off switch.
The only complaint my husband had was that it didn't feel very secure under the laptop. He said he felt as if the laptop was going to slip off the cooling fan at any time.