MPA to WAV with WinAmp

Start WinAmp and open the mpa-stream.

Click on the left edge, then the WinAmp Menu will appear.
Now click on "Options" "Preferences"...

Now select under "Plug-ins" the "Nullsoft Disk Writer" and click on "Configure".
Select your output folder.
Hit "Close" to go back to WinAmp

Then simply click on "Play" and the WAV will be created.
When WinAmp is finished go back to the options and select "Nullsoft DirectSound".