Software to measure CPU power dissipation

Solution
CoreTemp has a "power" figure that updates in real-time. This doesn't necessarily perfectly reflect actual power consumption, but I've carefully measured my PC's power draw at the wall and found it to at least be a close approximation. I'm inclined to believe that it calculates this number, rather than reads it from any sensor.

http://www.alcpu.com/CoreTemp/php/download.php?id=3