RGB LED outdoor accent lights

Hello

I am a electrician that is installing led lights on a major highway in my town to accent the underside of the bridges and started thinking about how I can do this at home. These lights are from Martin and put out some 140 watts. I believe there are 3 different colored LEDs in the lights, but I am not sure. There appears to be 54 or so LEDs. How can I do this at home? I would like to have numerous lights all changing colors, but all be the same color. Computer controlled to slowly change??? What would I need to do this???

Please help a dumb electrician!!!!

Thanks
Andy

PWM is the most common, using a microcontroller. You could also do it straight of the PC. Since I don't know what you have on hand, what you work with, well basically don't know what you can do. But I can tell you there are literally hundreds of RGB moodlight projects posted all over the web. I'm happy with the Attiny13 version I put together (stole the code, fixed a little). Suggest you hit the search engine.