Site - http://www.wwpi.com See the screen shot. Likely something in the CSS. This only occurs in IE8. Thanks.
Have you looked at other Joomla sites to see if the problem is with Joomla or just with your own template or your own css?
oh man , I had the same problem one time with IE and took a developer to fix it thats why I hate IE ! it is something for sure in CSS , fixing it is not easy , as sometimes there is no wrong code , just needs a trick to be compatible to some browsers.
Check the joomla forums there usually are answers to most common problems and that is a common one happened to me once .