These are pre-wired LEDs with a shift register like chip on each LED.
This product best described each individual LED.
This product is a string of them.
This is the closest looking item to the product I use, but the chip is the same as the above ones.
http://www.bliptronics.com/item.aspx?ItemID=98
You can use code from bliptronics if using those lights or the nice fastspi library to control any of them.
Do not forget you need power - lots of DC power. 60ma per LED, so 50 LEDs is 3 amps and 15 watts.
I get mine from the factory in bulk via special order - but any of the above items should do the trick.
Hopes that gets you going in the right direction.