Grab a portable version of Firefox 4.0 beta 1, test it safely and easily
I've only tested it for a few minutes, but it seems to be fully-featured and as fast as the real deal (which you can download here). The only difference is that it doesn't require installation, so you can run it from a USB memory stick, or anywhere else.
Users of the PortableApps Platform can do some other funky things with it, but that's outside the scope of this article (in fact, we should totally write something about PortableApps...)
Oh, our guide on removing Firefox's big orange button works with this portable version! Simply navigate to FirefoxPortableTest > Data > Profile > chrome and dump userChrome.css in there.