This add-on works in two ways: 1. It adds the "ui-corner-..." css classes to the boxes. These only work for browsers who support the -moz-border-radius, -webkit-border-radius or border-radius property, including but not limited to: Mozilla Firefox (version 2.0 onward), Opera (version 10.5 onward), Safari (version 3.1 onward), Chrome (version 4 onward), Internet Explorer (version 9 onward), iOS Safari (version 3.2 onward), Opera Mobile (version 11 onward) and Android Browser (version 2.1 onward). 2. Uses a header tag module that emulates round corners using JavaScript that is included when the customer's browser is Internet Explorer version 8 and below. I only take credit for the OsCommerce add-on. I used Malsup's Jquery corner plugin (http://jquery.malsup.com/corner/) The Jquery plugin was originally written by Dave Methvin (http://methvin.com/jquery/jq-corner.html) The Jquery project is now hosted on Github (http://github.com/malsup/corner) Full add-on and instructions included. - Fedon Dimopoulos