Google released a nice little script that warns users that IE6 is way out of date. Just include a chunk of javascript, and Google takes care of the rest.
If we all adopted this route, then the Google’s warning screen would become standard, more trusted, and would probably do much better than all of us just showing our own error messages, warnings, or flat-out letting IE6 users see some garbled mess.

Google doesn't like IE6

Steve
2009.04.15
And you know what else is nice of Google? They put their Chrome browser as the last one! Sure, this might just be a simple technique, but I think some appreciation is called for.
Jim Jamesson
2009.04.16
Doesn’t some nav bar psychology theory say that the last menu item is clicked more than items in the middle?
Steve
2009.04.16
Yeah, that’s what I was referring to in ‘simple technique’ in the above comment. I’m pretty sure that’s why it’s not in between Safari and Opera.