W3CSchools has stats for IE6 usage at about 15%, as of May 2009. IE6 in Enterprise environment is still being used,
It’s steadily dropping because of the wide acceptance of Firefox, and Corporations are proactively upgrading to IE7 or IE8. This number will change dramatically when Enterprise favors Windows 7 as the new standard for productivity machines.
Some websites have already taken steps to prevent IE6 from loading their site. I can only applaud their efforts.