3 columns CSS
Far left column
This column has been floated to the far left, just by naming it first. These columns don't need to have different backgrounds; it's just to make them appear more distinct.
2nd left (or middle) column
This column is floated left, but named second in the page source code.
The next div (the one with the ads) needs the clear:left; clear:right; tag to prevent the floating from continuing into the next div.
To prevent overlapping the div below, make your middle section the longest! Blogs are a good example of this (esp Blogger).
Far right
This column is floated to the right.
The different browsers (IE, Firefox, Opera) add up widths in slightly different ways, so one has to leave a bit out! The parent div has width 750px, but if each of these was set to 250px, the result would overflow in Firefox and Opera.
