Forum Moderators: not2easy
<div style="width:800px;background-image:url('background.png')">
<div style="float:left;width:200px;">Left Column</div>
<div style="float:left;width:600px;">Right Column</div>
<br style="clear:both">
</div>
The two floated divs inside have no background image of their own and so you can see through them to the main background image.
This is the standard technique for making your divs equal length - i.e. using the background image which contains the DIV border lines and colours to fake the effect.
Good luck!