You may not need the netcraft toolbar, just try the test first without it. I don't have it and my standard version of FF didn't fall for the vulnerability, read my post again.
In FF3b4 without netcraft (impossible to install anyway) the link looks like normal, no phishing at all. We need an urgent update from Netcraft here!!!
When I put the pointer on the link to the test site, the status bar of my Firefox 3 beta 4 without the Netcraft add-on shows
http://www%2Emicrosoft%2Ecom%01%00@secunia.com/internet_explorer_address_bar_spoofing_test/
And when I try to proceed, there comes a warning with yes/no buttons.
You are about to log in to the site "secunia.com" with the username "www%2Emicrosoft%2Ecom%01%00", but the website does not require authentication. This may be an attempt to trick you.
Is "secunia.com" the site you want to visit?
So FF3b4 is less secure than FF2.0.0.13, I would be very surprised if that is the case.
It's beta, so in some cases, it could be possible but I wonder if this is the case.
Do you have noscript installed ?
Even when I temporally permit the secunia site, I still see the same thing.