I know this is an old question, but there is a simple, one line solution which works consistently for Chrome, Firefox, etc., as well as IE8 and above (and, for the most part, works on IE7 too – see http://www.quirksmode.org/css/selectors/ for details):
table td + td { border-left:2px solid red; }
The output is something like this:
Col1 | Col2 | Col3
What is making this work is that you are defining a border only on table cells which are adjacent to another table cell. In other words, you’re applying the CSS to all cells in a row except the first one.
By applying a left border to the second through the last child, it gives the appearance of the line being “between” the cells.