This is a great little bit of code for converting a folder of M4A files into MP3 files to be used by a Flash Audio player. You can find more about converting files on a Linux server at this wonderful Wiki page.
#!/bin/bash
for i in *.m4a; do
# out=$(echo $i | sed -e 's/.m4a//g')
# mplayer -ao pcm "$i" -ao pcm:file="${i%.m4a}.mp3"
faad -o - "$i" | lame - "${i%.m4a}.mp3"
done