Firefox 5 expected very soon as Firefox gearing up with 4 Rc 1
Firefox 5 release is now expected in June, where already Mozilla gearing up by releasing Firefox 4 beta 1 (alpha 1) which gives you indication of speeding up the developement process of Firefox 5 final release. After final release of Firefox 4, this Alpha release came up few hours back which give indication that how thick and fast developement of browser is getting in.
Mozilla and Firefox developers called it Nightly build version and its for testing purpose but still available for Download.
If you observed the design of new Firefox 4, it is turning out to be little similar to Chrome where tabs are opened on the top of the menu. which give indication that they are follow more or less same pattern.
Any how how you go with the download