I know this is old, and it might even be from the old o'blog, but I ran across it again and thought I'd put it in here. A very graphical explanation of how sub-pixel rendering works that you see being used in the font smoothing algorithms of XP and OS X. The last time I looked at this, I didn't have an LCD, so I didn't think it was that impressive. This time however, I have a dual monitor setup of 1 LCD and 1 CRT. Let me say it's pretty amazing what happens when I drag the sample images from one monitor to the next.

http://www.grc.com/ctwhat.htm