I am using a Dell Inspiron 1501, and I have the same problem.
The heat only seems to affect the laptop's performance slightly, and is usually not enough of a problem to be concerned about.
The general rule of thumb is that laptops do tend to generate more heat than desktop units because of the fact that they are confined to less than a fourth of the space, but expected to pull the same workload.
In my opinion, the heat is normal and is probably nothing to worry about, especially if you are performing intense tasks that require lots of power from your computer. Just be careful not to burn yourself.
