I'm using background images to create curved boxes. There's 5 images in total - 4 corner images and one 'dot' that's repeated along the horizontal and vertical edges. There's 8 divs - one for each corner, one for the top and bottom (repeated horizontally), and one for the left and right (repeated vertically).
In IE the borders for some of the boxes have gaps in them and I have no idea why. You can see this in action at: http://www.programmersheaven.com/csstest/display5.html.