OMG, this is easy and if you are a student or faculty member that has access to Dreamspark or MSDNAA.  If you are creating a game using Expression Blend 3 or Silverlight, you might find that you need to convert a .WAV file to a .WMA file.  This is easy to do using Encoder.

Click on Encode to start the encoding. The encode button is found on the bottom of the screen.
The files will be encoded or changed to WMA, quickly even on low end machines. The target is defaulted to the Expression folder in Documents or the My Documents library

That’s it, free to people who can access Dreamspark or MSDNAA!