This is a Firefox theme I have been working on. As the title states, it is based on the Firefox 4.0 mockups that have recently been floating round the net. It's called Strata40. It will transform your Firefox browser into a convincing Firefox 4 lookalike.

Go here to download this theme and for installation instructions. It's easier than it looks

And that's it! Enjoy this Firefox 4 lookalike theme and tutorial