css3pie

PIE (Progressive Internet Explorer) is a new beta project which aims to provide support for missed CSS3 features in Internet Explorer 6 to 8, if you can’t wait anymore you should have a look here. Actually features covered include border-radius, box-shadow, border-image, multiple background images, and linear-gradient as background image. Other features are under active development, sounds cool. To enable PIE library in your CSS, you will have to add a behaviour rule :

#myElement {
...
behavior: url(PIE.htc);
}

PIE is still a young project with big and very promising plans. Check the only available demo here, download PIE from github. Released under an Apache 2 license.