I apologize if this was posted before here, but it was too good to pass up and not let folks know. There's a really nice write up on colorspaces at this link:
Page 2 is really good, but give it a few minutes to load all the background images before you start mousing over the table.
It is fairly technical, and took me a couple of re-reads to sink in. If it's all too deep, at least take a look at page 3.