One of the more common problems with a no start condition with the Twin Cam engines is the crank position sensor.
It's located on the front of the engine near the oil filter. It's the sensor that is usually in the way when you remove the oil filter.
It will give you a crank but no start condition and the sensor itself is an easy replacement.
There has been an upgrade to the sensor in 04 because of problems with the previous manufacturer.

Below is some info on the changes to make identification easier.

http://www.box.net/shared/3zo8zkp184