http://goog-ajaxslt.sourceforge.net/
Google have released under the BSD License Javascript code for performing AJAX and XSLT operations in most modern browsers.
It appears to be compatible with (amongst other browsers) only version 6 of Internet Explorer, leaving out the 7% of IE5.x users (still a significant amount). On a commercial piece of software that’s interesting – Google need as near universal support as possible, but they’ve chosen to either reject the users outright or degrade to a plain HTML version (as with GMail) over including IE5 support in this package.
Still, as more and more applications come online designed to work with XSLT and AJAX surely the incentive can only increase for users to upgrade their PCs.