Yes! mod_transform works great. :-)
It is super simple and works as you'd expect. There are a couple of interesting features - XSL caching, the ability to turn on / off the module announcement (compare that to mod_xslt!), and the ability to map any includes to the webserver documentroot. Oh how that has bugged the heck out of me in my work with nexista! It uses the same xslt library as php, but as niq points out, without the overhead.
Question though, what's the mod_transform license?
UPDATE November 3, 2007: I am having problems with mod_transform and http caching. If neither the xml nor the xsl document has been modified since the last request, Apache sends a 304 response, but for some reason, the browser gets a 200 response, and fails. Not sure what the problem is though. I just set the Apache header to no-store, and no-cache, and its working now, so I guess you just can't use modification times. I remember reading something about that for server side includes. If you are going to have static-enough data, you might as well render it to html, or use a proxy cache of sorts.