Mozilla released the beta version of  Firefox 4, the upcoming build of the popular web browser for Windows, Mac OS and Linux. The Mozilla Firefox 4 has a redesigned user interface that  replaces the position of tabs to the top of the browser.

There is a  new Firefox button with all the options of the browser arranged together for easy access. Firefox 4 loads quick and open web pages fast. Other features of Mozilla Firefox 4 includes  "switch to tab", "App tab, WebM HD video support and  fix for common security vulnerabilities.

Find More - http://www.freewindowstips.com/2010/09/01/download-firefox-4-portable-usb-installer/