My little Script doing all the Stuff

m4a2mp3.sh

#!/bin/bash
#
#aptitude install mplayer twolame
#
for i in *.m4a; do
	echo "Convert: ${i%.m4a}.mp3"
	mplayer -ao pcm:file="${i%.m4a}.wav" "$i"	
	twolame "${i%.m4a}.wav" "${i%.m4a}.mp3"
	rm "${i%.m4a}.wav"
done

or
wma2mp3.sh

#!/bin/bash
#
#aptitude install mplayer twolame
#
for i in *.wma; do
	echo "Convert: ${i%.wma}.mp3"
	mplayer -ao pcm:file="${i%.wma}.wav" "$i"	
	twolame "${i%.wma}.wav" "${i%.wma}.mp3"
	rm "${i%.wma}.wav"
done

Just call “m4a2mp3.sh” of “wma2mp3.sh” in the dir where the files are 😀