This one is touchy, as it uses the javaview applet, and it only really works (yeah, right) with Internet explorer. I find that with Firefox, I can select my file format output options, but the part download does not work. With IE, I'm able to download a file, but not select file format options.
Probably works great if you're using Inventor 6. That seems to be the preferred format. (although Catia is in the list)