I need to style a
This code needs to be compatible with all major browsers. Also, does anyone know how to disable the mac "default" form look so I can design mine from within the browser?
You would probably be better off simulating the select some other way, rather than trying to CSS style a select form control.
Here's a support grid, that makes it clear you're doomed to fail with CSS: http://www.electrictoolbox.com/style-select-optgroup-options-css/
In addition to the second link Tony points to: http://www.456bereastreet.com/lab/form_controls/select/ full of examples of how to style a dropdown.