You have probably seen these forms of advertisings where you can peel a corner of a website and see a message underneath. SohTanaka has made a tutorial: Simple Page Peel Effect with jQuery & CSS. All they are doing is expanding the image on hover, then retracting to its default size on hover out.
You may also interested in The Sexy Curls jQuery Plugin if you like this tutorial. The page corner can be set to curl automatically. The plugin is released under the MIT license. That means you can do whatever you like with it.
Requirements: jQuery Framework
License: MIT License