I had Pixie on my computer for quite a while and had been enjoy it ever since I discovered it. Now, I came cross this even better tool, Color Schemer ColorPix, that does the same thing and even a little bit more. It's also free!
ColorPix is a useful little color picker that grabs the pixel under your mouse and transforms it into a number of different color formats.
You can use the built-in magnifier to zoom in on your screen, click on a color value to copy it directly to the clipboard, and even keep ColorPix on top of all other apps and out of the way.
Best of all, there's nothing to install - just download the tiny app and off you go. So grab it now, it's FREE!