> These are white LEDs, that is, blue LEDs covered with a white-light-emitting phosphor Could someone explain that a bit more please?
There are two ways to get white light (which is light of "all" visible wavelengths) from a LED: combining a red, a green and a blue LED, or using a coating that when energized by (typically blue) light, in turn reacts and emits white light.
You can read more at http://en.wikipedia.org/wiki/Light-emitting_diode#White_ligh..., of course.
Note: I'm just an (embedded) software guy with a hobby interest in electronics. :)