Here's fast post for people who don't know from where they can download Mozilla Firefox 4 Beta 1, Mozilla announced the new version of Firefox but people having difficulty to download it, so I got the links below after the jump..
We Don't have a change log for the new features, but it's really cool, you have to give it a try!
Download Mozilla Firefox 4 Beta 1 for Windows
Download Mozilla Firefox 4 Beta 1 for Mac
Download Mozilla Firefox 4 Beta 1 for Linux