Critique my table-less CSS plz!

Hi, thanks everyone who helped me out with CSS standards. Can you guys check out a little page I mocked up to see if I’m doing it right?


p.s. can anyone link me to a tutorial on positioning? I was curious as to how I might layout a browser-wide footer UNDER the three columns…especially when the height of the center column is set to auto and you can’t specify excactly how the height will work out. (picture below)