Mozilla has unveiled the third beta release of Firefox 3. The new release isn't quite complete and bug-free, and it's aimed largely at developers and enthusiasts, but it nonetheless gives a good idea of what's in store for the final Firefox 3.0 release. Firefox 3 Beta 3 introduces new user interfaces tailored to Windows Vista, Windows XP, Linux, and Mac OS X. The browser features a different theme for each operating system, attempting to mirror Internet Explorer 7 on Windows and Safari on OS X. There's also a new download manager, improved plug-in and add-on management, one-click site information, better malware protection, fancier address bar auto-complete, and the promise of improved performance as well as lower memory utilization. The folks at Ars Technica have a quick walkthrough of the Beta 3 release here with some screenshots to show how the browser looks in different OSes. Those interested in taking Beta 3 for a spin can download it from this page for Windows, Mac OS X, and Linux in more than 30 languages. This being beta software, we suggest that users exercise caution. Firefox 2 users should probably back up their profile directory before installing Firefox 3 Beta 3.