I think it makes sense to include wma support for the win version, since pc users may have a ton of wma files. If I was someone who had never used a mac or itunes before, maybe someone who didn't care about the differences between formats and OS's, I'd be pissed if I tried to play a wma that worked before, and didn't work in the new app I had just downloaded. "iTunes is cool, but....it doesn't even play wma's". Don't let them export to wma, but at least let them play them so they don't have to have two apps for music, or convert a ton of files or something.