Look Plus! over,  with at over 2 dozen great tools.

Captures below to show how easy it is to encode MP3 files to WMA. 

 
I selected 14 mp3's (Have done over a 100 in one fell swoop) When selected, I right clicked on selected group and got below . . .
 
 
Less than 7 minutes later I got below.
 
 
Just encoded this song for comparison using !Plus, took 17 sec at 32 kbps . . .
http://unclegus.150m.com/!Jazz/Neil_Sedaka_Oh_Carol_Plus.wma
 
Using Windows Media 9 Encoder.
 http://unclegus.150m.com/!Jazz/Neil_Sedaka_Oh_Carol.wma

Check here for more Media Encoders to come shortly.

 
Have fun 

Uncle Gus