The Motherboard Monitor is a handy little program that can read information from the sensors on your motherboard to report such useful things as the temperature of your processor, the board itself, and the ambient temp in your case. It can also read voltages, current CPU speeds, and basically anything else that your mobo can read out.

It's very flexible and lets you put readouts in the system tray, as well as log them to a text file. I found it a godsend in that very paranoid period after I had built my first computer when I was constantly worrying that I was going to smoke my overclocked CPU. It's too bad that it's only ported to Windows 9x, I'm sure those wacky mac and linux users could find use for it as well.

You can find it at http://mbm.livewiredev.com/