I had the same problem with .wma, have no idea if they are unprotected or not.
I read somewhere about using Switch to convert .wma to .mp3. So I downloaded both Switch and Flip4Mac (which was required to be had at the same time) but it seems to convert anything BUT .wma. Anyhow, the Flip4Mac plugin allowed me to open the .wma in Quicktime and I tried saving it on Quicktime into an iPhone format, then open it with iTunes. It worked! Hope this helps.
I read somewhere about using Switch to convert .wma to .mp3. So I downloaded both Switch and Flip4Mac (which was required to be had at the same time) but it seems to convert anything BUT .wma. Anyhow, the Flip4Mac plugin allowed me to open the .wma in Quicktime and I tried saving it on Quicktime into an iPhone format, then open it with iTunes. It worked! Hope this helps.