How do I programmatically convert mp3 to an itunes-playable aac/m4a file?

ffmpeg -i source.mp3 -acodec libfaac -ab 128k dest.aac

#!/bin/sh

TARGET=$1

BASE=`basename "${TARGET}"`
echo TARGET: "${TARGET}"
echo BASE:   "${BASE}" .m4a

# Warning! Race condition vulnerability here! Should use a mktemp
# variant or something...
mkfifo encode
mplayer -quiet -ao pcm -aofile encode "${TARGET}" &
lame --silent encode "${BASE}".mp3
rm encode