Ever hear of a thing called RGB? Red, Green, Blue? How about an RGB LED? These 5mm units have four pins: one for each colour and a common anode. Use this one LED for three status indicators or pulse width modulate all three and get mixed colors!
Note: The datasheet below is for the common cathode version of these LEDs, all of the values are the same except that instead of sharing a cathode, these share an anode. An updated datasheet will be added as soon as possible.