Anyone know where and what color is the Reverse Wire on a 2000 Chevrolet Venture?

You can use the wire going to one of the reverse bulbs in your taillights.

Don't splice into the tailights, that is a PITA, all the wiring you have to run and just in general time consuming. Splice into the wire at A2, light green and black, shown on this picture. It is located on the right side of your sterring column and behind your instrument panel.