” Mozilla’s Firefox OS (also known as Boot to Gecko), a mobile operating system that focuses on web technologies like HTML, CSS and JavaScript, is quickly moving through its development stages. While it’s already possible to install Firefox OS on many phones, the Firefox OS team today launched its Firefox OS Simulator. The simulator, which is still considered “experimental,” is basically a Firefox add-on that should run on Windows, Mac and Linux (though there are currently some known issues with Linux and Windows XP).
“Once installed, the simulator will automatically keep itself updated with the latest snapshots from the Boot to Gecko (B2G) project … “

 Source: TechCrunch
 Mozilla Launches Experimental Browser-Based Simulator For Firefox OS

Go get it.