Well, QuickTime is buit into OS X as least in recent versions (I'm running Mavericks) but will not natively play a WMA file unless a codec is added - see the screen capture below from this Apple Support Article - seems like the Flip4Mac codec is needed; if interested, go to the link - NOW, I've not used this QuickTime 'add-in', so no personal experience - if you do give the codec a try let us know your results.
Also, there is third party software that can be used (simply google 'WMA to MP3 conversion Mac') - a program that I used previously on my Windows machine was Switch Audio File Converter - seems to be a $30 purchase (not sure if there is a trial period - check link,if interested). Adapter is another program (free) that I've read about but have not given it a try - not sure if the app does 'WMA to Other Apple compatible codecs'? Good luck - Dave
Hi again J-writer - I hope that you'll return to the forum?
BUT, out of curiosity, I did a DL and install of Adapter (linked in my first post) - also did a DL of a WMA file (flute song) - would not play in QuickTime, but using Adapter, I was able to convert to MP3 (other options are available) and the file then played fine on my MBPro - have not explored all of its features, but a free option. Dave