CSS Rounded Corners Round-up
If you wanted a central location on how to create Rounded Corners with CSS, this is the place.
If you have a "Web 2.0" site, you more than likely have rounded corners in one area of your site. Right?
If not, I would recommend getting some rounded corners. Smiley Cat contains an entire CSS Rounded Corners Round-Up with just about every site I've seen of CSS techniques of rounded corners.
This is a definite bookmark.