Why not start with something like this:

http://www.radioshack.com/sm-whats-a...i-2117994.html

It will teach you basics of microcontrollers, so you can learn to write your own programs. It even includes a "reaction timer" example. Or get a beginners book on PIC BASIC, which will also have examples to get you going in the right direction.

I think many people here could write that program for you in about 20 minutes, but then what have YOU learned? If you do it yourself you will also be much more qualified to document the project. If you understand just a FEW basic commands, then this should be a very easy project.

If you run into problems, then this forum is a great place to get help. But you need to at least TRY. Not just ask for some pre-written code.