Finished this last night. Thought I'd throw it out there for those thinking about trying it. After reading several other DIY threads I took the plunge. Ordered my blue LEDs from evilmadscience.com - Evil Mad Science Shop
Used this LED calculater: LED series parallel array wizard
and got some resistors from Fry's.
With my setup, 20 gallon and DIY CFL lighting, I didn't have enough room in the hood to put the LED's, so I just mounted them on a cut piece of wood on the the back of my aquarium. Sealed/glued the LEDs and wiring with some clear silicone adhesive.
Added a 500 ohm potentiometer to lower the lighting in case it was needed. Glad I did, cause it ended up being a little to bright I thought. One thing that was really cool after I got it setup and installed was one of the LEDs was shining right above where my HOB Fluval filter was dispensing. Made the light glimmer and move, creating a under-ocean effect. Maybe I'll add a power head later to accentuate the affect with the rest of the LEDs. Used an old cell phone charger for the power supply.
Anyway, I was pretty pleased with the result. It was all fun and games while I was enjoying my labor till my beautiful yellow guppy took a 3 1/2 foot header out the back of the tank onto a concrete floor. He was swimming a little funny for a while after I put him back in. lol. Maybe he was pissed at the LED's. Here are a few pics (I hope). The tank pic was at max luminosity. Turned it down after taking the picture. Let me know if you guys want more details or pictures.