Mozilla is officially getting into the OS business early next year with Firefox OS, the new name for the long-time coming Boot 2 Gecko project. The operating system will run on smartphones and be entirely dependent upon HTML5 for all of its apps. Mozilla is now offering developers a chance to try out the Firefox OS on desktop first before the phone version hits next year.
On a Mozilla blog, the company details how they've been building up a team to work on Firefox OS. The phone OS they're currently working on will consist of three layers - Gonk, Gecko and Gaia. Gonk consists of the kernel, low-level components, Gecko is the rendering APIs and Gaia is the HTML5 and UI layer. They will be aggressively testing these features with nightly builds for anybody to play around with.
This is where you, the developer, comes in. The Firefox OS team has released desktop builds of the OS and are updating it daily. You can download it now and play around with all the features. Developers can even build their own Web app and test it against the OS to see if it runs. This is the same kind of software app developers use to make apps on Android or iOS.
If you want to help contribute to Firefox OS, you're going to need to set up a Gaia profile. Mozilla offers an easy set of instructions to set up your own Gaia profile. For more information about the Firefox OS project, hit up the MozillaWiki. You can download the Firefox OS from here.