Not to steal an idea/thread from Xela, but hell, it was a good idea...I did some research into my training device; the Kurt Kinetic Road Machine and found that they have a simple formula for calculating power from the speed of the rear wheel.
If you have a Kurt Kinetic trainer and want to know what type of power your putting out, here is the link
Kinetic by Kurt: Power Curve.
They claim that it will be accurate to +- 3%.
I am going to test out the forumlas this weekend when I attack The Sufferfest videos and I will post the results.