- Make the column stretchy, then stick this in the column:
<img class="MinWidthPix" src="/images/pix.gif">
- And stick this in the stylesheet
.MinWidthPix {width:500px;height:1px;}
- pix.gif is a 1x1 transparent gif
Dana also mentioned that, instead of a 1x1 pix, a HR tag could also work, but that the HR tag is prone to result in inconsistencies in different browsers.