Now one can create rounded corners without using images or javascript with the help of spiffycorners. It is an online tool that provide easy way to generate HTML and CSS code for the box.
You can use this code to generate basic code and then can play with it as per requirement, like we all generally do !
You need to enter only 3 fields: name of the class, background color and foreground color and then hit the button to get your CSS and HTML code (see pic)
So get set playing around with this. Also there is another cool online service called SpiffyBox. What is this all about, well check the site and you will know.