The best solution I have found for moon lighting is a cold cathode light tube that people put in their computer cases to make them glow. I find these nicer than the LED lights as the light is more diffused and you don't end up with spotlights in your tank. These lights are available at many computer stores for ~ $20.00 CDN including a nice on/off toggle switch and adhesive velcro tabs for mounting. Here is where I got mine so you can see what they look like:
http://www.memoryexpress.com/FrameColdCathodeLight.php
I would reccomend the "Cold Cathode Kit, 30cm, Blue" for each 4" of tank, and the "Cold Cathode Kit, 10cm, Blue" for <3' wide tanks. You can adjust the intensity by re-positioning the light(I have mine just sitting on top inlet pipes of the middle back edge of my tank now). The only other item you will need is a cheap acc/dc converter to plug into the wall(I cut mine off an old pair of computer speakers). Make sure the voltage and amperage is correct or you will blow the light. For the 30 cm one I have a 12V / 200 ma converter is perfect. Here are some pics, maybe not the greatest but you get the idea...
Evan.