Led Design Help

I would like to design a super blue leg lights for my fish tank. I have found other designs but they are not what I am looking for.
I would like to use 6 super blue led with 475 wavelength that has a 8 hours on timer and the remaining time off, using a 12vac 300ma or one equivelant. power supplie. I am totaly clueless on how to design such a circuit board. I need to know what type of resistors, timing chip, ect. Basicly what the scymatics would look like and a discription on how to make the circuit board.
If I am missing anything let me know Please
frenchy124
frenchman124@msn.com

You can purchase a timer from Radio Shack, or many hardware stores, that you plug into the outlet and plug your 12VAC power supply into the timer. If you connect two LEDs back to back, it is not necessary to rectify the AC, just put 470 ohms in series with the pair, or if you want it real bright, use 270 ohms.