unFocus History Keeper is a JavaScript based deep linking and browser history (back button) management library for single page browser based applications, also called RIAs, and usually based on Adobe Flash Player or Ajax, though this should work with other scriptable runtimes as well, such as Microsoft's SilverLight or Sun's JavaFX.
Please visit unFocus.History Keeper's home page on unfocus.com for more (up to date) info!