This weekend i've implemented the file upload feature (using an ajax file upload) which uploads the file to X place (defined in the doajaxfileupload.php file) and displays a link for the user to use later.
I would like some feedback... we're using it for a project i'm working on actually... and i'll get my team's feedback but would be nice to have even more...
i've generated a patch file, which is http://codigo.zarate.net.ve/phpfreechat/uploadfile-plugin.patch
feel free to contact me (either by forum, or using the mail function of the forums

Have fun,
Santiago Zarate