they're a bit expensive, but they'll leave spots on your eyes for days.
for a cheap source look at microchip.com, you'll get 5 of them soldered onto a board
the boost board gives out 40v to provide enough voltage for the 5 LED's in series, it runs off of 9v. they're a blueish white, like the xenon headlights.
i think it's the 1630 boost board comes with it.