If you were running the Windows version of iTunes, then it did and it does now. The Mac version never did and doesn't now. What this gets down to is that there has been absolutely no change in how iTunes handles .wma files on either platform.
so i have upgraded to itunes 10 and now i can't figure out how to arrange my music by date added. i had it all arranged that way in previous versions but as soon as i upgraded i can't find that as an option. can anyone help?