Mozilla have rolled out the beta version of Firefox 4 for people to try out. Head over the Firefox 4 Beta
download page for a link to grab it.
There's a few changes so far:
-Tabs have been moved to above the address bar Chrome-style.
-There's a Firefox button (read: MS Office ribbon) to access all menu functions from.
-An apps tab (keep web apps you use frequently open permanently).
-Improved add-on management, upgraded privacy controls and more
There's also promises that upcoming releases of the beta will add in more features including the ability to sync your bookmarks, saved passwords, settings & more to the clouds (like Opera) and retrieve on any PC you use.
The obvious downside is that a lot of extensions currently don't support it, however Adblock Plus does! promoted forum item