My site was hacked using the paid version of the plugin available here: http://pageflipgallery.com/. I was on WordPress 3.0.4 when this happened last week, and have since upgraded. Flipping Book version was 0.5.11.6. With the help of my hosting provider, we managed to locate 22 files within the plugin folder were encrypted with some very spammy/malicious code in the "flippingbook-wp-gallery-personal" and "page-flip-image-gallery". Thankfully, the rest of my WordPress system has not been compromised, at least to my knowledge after manually checking lots of files. This plugin has caused me lots of problems and I would highly recommend staying far away from it, and update WordPress as frequently as possible! Check your files right now if you use this plugin!