I find drag & dropping of the audio files directly onto the iTunes player interface -> Library folder is the easiest & fastest way. You can add multiple files at once. As far as wmp goes, just find where the songs it has are stored & add those also. As far as licensing goes .... if they're wma files I'm not sure as I don't normally use those type of files. I try to stay away from wma & its DRM licencing issues.