Here are few sites using it. ( Please let me know if you are using it, I will add a link here)

http://www.yootheme.com/demo/wordpress/radiance

http://www.itsfirefly.com/

http://www.quazarwebdesign.com/

http://www.haelu.co.nf/


Documentation: http://www.backslash.gr/content/blog/webdevelopment/10-jquery-firefly-plugin