I've been having a lot of fun, making curved boxes with CSS. Take any box, add

border: 2px;
border-color: #ff0000; (my color you like)
-moz-border-radius: 15px; ( radiuis of the corners, firefox code)
-webkit-border-radius: 15px; (chrome/safari code)
border-radius: 15px; (official CSS 2.1 code)

Finally get proper curved boxes without having to draw the edges and use background
images, which takes ages.

Trouble is it doesn't work in IE not even IE8, its been part of the CSS 2.1 standard
for years, but still not supported. Wish Microsoft would sort it out. Meanwhile ugly square boxes on MS's dumb browser.

border-radius is CSS3 isn't it?

Don't forget -khtml-border-radius as well.

Go to http://www.htmlremix.com/css/curved-...-cross-browser where there's some info on how to get curved borders in IE.

Of course it's not going to work in IE, you're using Mozilla and Webkit specific filters.
CSS3 will give us all better options, but it's not ready for primetime yet.

Are you running IE8 in compatibility mode?