I've noticed a few corporates who still need IE6 for some internal web apps also installing firefox recently due to not being able to have two versions of IE installed.
I always figured the absolute best way to support old IE6 developed intranet apps would be a single site browser tool with embedded IE6. Like fluid for windows.
The problem is Microsofts boneheaded decision to make IE systemwide. Upgrading to IE7 also upgrades all webcontrol instances. So this doesn't seem feasable.
