Windows Media Audio Conversion
First of all, there are 3 versions of Windows Media Audio:
WMA v2 - the original release. This uses Digital Rights Management version 1
WMA v7 - The second generation, first edition. This uses Digital Rights Management version 2
WMA v 8 - The latest one, also uses DRM version 2 and Microsoft are needlessly making a big deal out of it.
At the present time, it is possible to convert any unprotected wma audio file.
You can do the conversion by downloading the correct plugin for dBpoweramp music converter and using the internet audio guide. Make sure you download the correct plugin as there are different plugins for the different versions. Also note that although it says that the wma v2 codec is for encoding only, I can decode wma v2 files - but that's probably because I also have the v7 and v8 plugins installed as well.
Microsoft have enabled a system called Digital Rights Management that allows the person encoding the audio to lock the audio with a key that means that the file cannot be directly converted by programs (without breaking the law, that is).
This is annoying for several reasons that I'm sure you can imagine.
So, how do we get around this? Well there are currently two possible ways:
1) Remove the key. There is a program that you can find information about it here (and download it here) that is able to remove the encryption key from some WMAv7 and v8 files. It doesn't always work but it's worth a try.
2) Sample the song. Use the method described in the 3rd part of the internet audio guide and resample the song directly.
I do not know of any other methods of converting protected WMA files at present. If I get any more information, it will be posted here.