Here is one (not so pretty build):
http://www.marinecolorado.org/forums...-DIY-LED-build
Also take a look at post #6 here. This is one of the cleanest builds I have done. Sorry there is not a lot of info on that one.
http://www.marinecolorado.org/forums...lon-Pico-Build
Keep in mind that these were both for Saltwater tanks and therefore much more than would be needed for your tank. You could keep it very simple. My first LED build was made from a stock picotope light. I put a small Aluminum flat bar in it, added 5 LEDs and a buckpuck. I worked great for my first little light, plus it looked stock. That is one great thing about LEDs, you can fit them in just about any old fixture you have laying around.