Duplicate:
What is the best way to create rounded corners
How to make a cross browser, W3C valid, semantic, non-javascript ROUND corner?
What techniques (That are standards compliant) are there for putting rounded corners on display elements in an HTML page?
I put HTML CSS and javascript on the tag list below because I believe they are fairly ubiquitous, but if you have a technique that uses other techniques that may be used and are (relatively) reliable across standard browsers that works as well, but please put a note on what browsers fail.