Ahh IE6 will you never die?
There's a whole posting just about the persistence of IE6 in the enterprise, and why it will probably never die entirely over at the 360 blog:
http://360is.blogspot.com/2010/11/ie6-will-no-one-rid-me-of-this.html
Remember kids, when you create a non-portable in-house web application, don't trust Microsoft (or anyone else) to continue supporting you any longer than _they_ want to.
AG