I was recently shown this website for liquid layouts using CSS. http://matthewjamestaylor.com/blog/perfect-multi-column-liquid-layouts (Take a look at the demo pages in the links below).
The author now provides an example for fixed width layouts. Check out; http://matthewjamestaylor.com/blog/how-to-convert-a-liquid-layout-to-fixed-width.
This provides the following example(s), http://matthewjamestaylor.com/blog/ultimate-2-column-left-menu-pixels.htm (for two column layout like you are after I think)
http://matthewjamestaylor.com/blog/fixed-width-or-liquid-layout.htm (for three column layout).
Sorry for so many links to this guys site, but I think it is an AWESOME resource.