Thought you were going to do this with the menu section?
And a warning = It is up to the browser as to wither iframes works. I use FF and have it so everything opens in a new tab and I think most people do this. So it may be better to use AJAX to do this.
But here is the iframe way:
<a href="http://www.yahoo.com" target="here">YAHOO</a>
<iframe src="test_2.html" width="600px;" height="300px;" name="here" style="float:right;">
<p>Your browser does not support iframes.</p>