The next major upgrade for the popular open source Web browser is available for Mac, Windows and Linux.
There are lots of new features, you can read about them in the release notes. This beta version of Firefox is said to be stable for daily browsing.
"Once you download Firefox 4 Beta 1," Mozilla's Director of Firefox Mike Beltzner said, "you're part of our beta program and will receive regular updates as more features launch. We've included a Feedback Add-On that helps you let us know what you think about the new features and technologies in the beta."