The problem is that you can't run IE6 and IE8 in parallel (though it sounds like adbachman may have a way around this). So you keep IE6 for applications in your intranet that require it and use Firefox for general web access.
But the point is that that's possible now, but corporations aren't doing it. As long as IE6 exists on the computer as a general web-browsing solution, and is required for something, they'll be loath to install and maintain "another, redundant" web browser for anything else. To stop this practice, we have to take IE6-the-browser away completely, and in its place give IE6-the-hardwired-intranet-client.
In most of the companies I've worked for in the last decade, including a fair bit in systems administration I've see the following used as the solution.
USER: I have a problem.
TECH: Let's see...hey! Why do you have Firefox installed?
USER: It works better than IE6. Why are you guys using old crap like that? I thought we were a modern company...
TECH: We are modern, except for IE6.
USER: So I have to uninstall it?
TECH: I can't "officially" support it.
USER: Aaaah.
TECH: OK, your print queue is cleared.
Where I work the conversation would go something like this: TECH: Who gave you permission to use uncertified software? USER: Uh, noone TECH: I'll have to make a report about this. MANAGER: You're fired.
That would be the user wearing the boot up his ass. Running unapproved software (e.g. portable FireFox on my locked down machine) would be grounds for immediate dismissal in this org. IE 6 forever (sigh)
