On my site here, the content drops to the bottom in my Firefox browser. And in IE6, why is the image in my banner dropping relative to the image to the left of it? Argghhhh
Its because IE6 doesn't handle margin property well. I usually use padding to align something. The problem in firefox is probably because of float property. The sum of the content container and siderbar probably are not equal to that of the container they are in. Not sure because I haven't checked the css code or the html markup.
The sum of the content and sidebar do equal the width so that isn't the problem. I used Firebug to reduce the width by quite a bit and it still doesn't float up properly.