I have uploaded a beta of JQCC2, based on the beta version 2.0 of the official script. This now includes support for jQuery 1.3.
There are still many optimisations to make and tests to perform, but the examples included in the zip work in IE6, IE7, Chrome, Safari, Firefox, and (excluding the CSS selector feature) Opera. My version does differ from the official script; mainly the fact that boxes are not fixed width/height.
If you find bugs, want to contribute fixes, or want to help extend the plugin please leave your comments.
Finally, special thanks to Terry Riegel, Cameron Cooke and Tim Hutchison who made the original CurvyCorners script; they did all the hard work!
Update: Beta 2 uploaded
Download: JQuery Curvy Corners 2 (2816)