If you have a laptop which gets hot - maybe even too hot to use comfortably on your lap - then you should really do something about it. Apart from the fact that it's annoying and uncomfortable, excessive heat can cause your laptop to age more quickly. Keeping it cooler will make if run better and last longer.
The best way to keep your laptop cool is to use a laptop cooling pad. there are two basic types - passive and active.
Passive laptop cooling pads don't use fans. They are usually just a hard surface, sometimes a mesh, which allows the air to circulate freely around the laptop. These work fairly well for low powered laptops or laptops which aren't used for long periods of time. They have the advantage that, since they don't have fans, they don't draw power and they don't create noise.
Active laptop cooling pads use fans to force additional air into your laptop's cooling vents - usually located on the bottom of the laptop. These work very well and can really drop the temperature of your laptop. However, they draw power for the fan - usually from the laptop's usb port - and the fan can also generate a little noise.
Here's a list of some different laptop cooling pads for you to review: