Great tutorial here about getting every type of rounded corner you can imagine, including the rounded-est corner of all–a circle!
Still on rounded corners, this blog showed and explained the basics, but check the list of posts to the right. I thought that there are quite a few good ones on a variety of topics that would be relevant to most of us.
Lastly, this is a really detailed CSS reference, and includes tutorials.
One thing I’ve found is that when I muck something up (often!) validating my XHTML and/or CSS helps me find the problem. Like when I removed, then replaced my page header, which then refused to appear, which meant other things on the page started moving around. Problem: I made a typo of one double, then one single quote around a div class, and it was highlighted in the errors. Or accidentally deleting a curly bracket. I doubt I would have found either very quickly if I’d spent ages staring at the code, though that is what I end up doing most of the time!
Julie
Reference
Border-radius: create rounded corners with CSS! – CSS3 . Info 2012, viewed 18 May 2012 , <http://www.css3.info/preview/rounded-border/>.
CSS – MDN, 2012, viewed 18 May 2012 , <https://developer.mozilla.org/en/CSS>.
CSS Rounded Corners In All Browsers (With No Images) | Jon Raasch’s Blog, 2012, viewed 18 May 2012 , <http://jonraasch.com/blog/css-rounded-corners-in-all-browsers>.