Round corners with CSS

Well... in my quest to make this blog a little less ugly, I searched for how to make round corners with CSS. I only knew how to make them with pictures and many of the articles I found about it, also used pictures. But not this one. That's what I'm using at the moment and seems to work just fine with Firefox and Opera 9.20 but not with Internet Explorer 6.0... what else is new?

I guess I'll read a bit more about this technique but I couldn't care less about IE 6 anyway. I'll try IE 7 when I have the chance.