How to Convert WMV file to MP3 for iTunes or Garageband
If you have some WMV video files you only need the audio but no video, you can compromise by extract audio from it and then listen to it. You might want to extract the episode or the audio of a movie for playback on your iPod, as ringtones for iPhone, or to create your own masterpiece in Garageband. The question is: how to convert WMV to MP3 for iTunes or Garageband?
If you already have QuickTime(Pro), and you are able to play the WMV file on Mac with QuickTime (Pro), you can use file/Export-->'Sound to wave' or 'Sound to aiff' to extract the audio track. After that, import the audio track into iTunes and you can convert it to MP3 format. Make sure that you install Flip4Mac or you won't be able to play WMV files (DRM WMV file excluded).
But it's not necessary to get QuickTime 7 Pro, which cost $29.99, to extract audio from WMV file. Quicktime Pro only allows you to export files playable in QuickTime Player to a format for iPhone, iPod, Apple TV or a variety of other devices. Since many popular video formats are not compatible with QuickTime, you need to install QuickTime components for separate formats. WMV Video Converter for Mac saves you the hassle of figuring out how to install all these components and provides a more powerful yet easy way to extract audio from WMV file.
You can download it for free:
How to extract auido from WMV to MP3 on Mac
1Drag your WMV videos to the program.

2Choose "MP3" as output format

This Mac WMV video converter can convert WMV video to all popular video formats for iPod, iPhone, PSP, PS3, Apple TV, MP4 players and MP3 players and so on. If you don't know what formats your device supports, you can just select the format according to your device's name.
3Start the WMV to MP3 Conversion on Mac
When you finish the output setting, just click the "Convert" button to start conversion. Let this WMV to MP3 Video Converter for Mac do the rest for you.