Ruzee Borders is the only Javascript-based anti-aliased rounded corner solution I've found that works in all major browsers (Firefox 2/3, Chrome, Safari 3, IE6/7/8), and ALSO the only one that works when both the rounded element AND the parent element contain a background image. It also does borders, shadows, and glowing.
The newer RUZEE.ShadedBorder is another option, but it lacks support for obtaining style information from CSS.
