I'm a student from QUT doing interaction design this semester (you've probably heard from a few of us over the past few months). Anyway I just order the 25 diffused RGB Leds if that rings a bell for you.
Now onto my project, Im basically building a 450mm3 white perspex cube that changes colour based on sound. On the inside of the cube I intend to build a smaller 5 sided cube structure from circuit borad and attach 4 RGB leds to each side of the inner cube at the corners to maximise the dispersion. I am using Arduino to attach a microphone to read the audio, and i then intend to connect the RGB leds to the pwm. However from what i have found out from my lecturer Gavin Sade, the leds will draw too much power as there will be 20 all up.
His solution was to use the BlinkM MaxM controller chip and connect my own circuit of 20 RGB leds and power according with something like a 5Volt 2am p power supply. I have little money to spend on this project unfortunately and from the looks of it this would be the cheapest way to go as I have already got my Arduino, RGB leds and microphone ready to go.. just need to work out a circuit to control that many leds.
http://www.littlebirdelectronics.com/products/Triple-Output-LED-RGB-Diffused-25pcs.html that is the rgb leds that im using. Ill be using 20 of them in my cube, utilising each colour it that makes any difference. I need to work out the power supply also to maximise the brightness potential of these lights. Also need to know how to set up correct resistors for this setup.