I\'ve seen a few fixes for allowing PNG images to have transparency in Internet Explorer 6, but I\'ve yet to find one that also allows you to set the background position in CSS.
You can actually use pure CSS to get positioned background images with alpha transparency in IE6 by taking advantage of IE6's alpha filters and the CSS clip
property. Julien Lecomte describes the technique on his blog.
Note that this technique does result in a performance hit for each use of an alpha filter.