Same here... lots of applications we wrote at work, are still in use on IE6 laptops.
We cannot upgrade, because then we would not be able to continue to support and expand our apps.
Moreover, we even used IE6 under Windows CE back in 2006 (that's how long it's been available, at least the original mobile IE6 version)... it was terrific to be able to use most IE6 DHTML features on a touch handheld. The application even had flick-scrolling like the iPhone later had.
You can see an old demo of the CE app here:
http://www.youtube.com/watch?v=E0bhG6d0n9w
(It's a bit boring, because it's a field technician application for a phone company.)