If you have used iTunes in default mode to create a library of music for your iPod you may need to convert the resulting .m4a files to .mp3 format. MPlayer can do this for you - here are the necessary commands, in the form of a simple shell script:
#!/bin/sh for FILE in *.m4a do mplayer.exe -vc null -vo null -ao pcm:fast $FILE -ao pcm:file="temp.wav" lame -h -V2 --vbr-new temp.wav `basename $FILE .m4a`.mp3 done
You will be left with a temp.wav file in the current directory - delete it (and the .m4a files, if you want) after the conversion.