This is a great/easy solution - thanks for posting this.
I spent maybe 5 minutes adding this to my site, and I have to say I'm impressed. Copy the file to your server, add one new tag to your css wherever your radius css defs are and viola, done.
Prior to using this I was able to get IE looking nearly identical to Chrome/FF/Safar - except for drop-shadows and rounded corners. I've been pretty strict about not deviating from the open standards and this has actually caused several arguments between me and one of my biz partners (he just doesn't get why I refuse to 'fix' the issue in IE with one of the graphic hacks out there - and has been seeking advice from designers about this even!).
So yeah, huge thanks again because not only does this solution thorough rocks for what I needed and took no time to implement, but also now my biz partner is going to have one less thing to fight with me about (and probably move back on to telling clients about new features he wants that I have't started yet...).