The client can automatically detect the music your're listening to. However this only works out-of-the-box if your're using XMMS or RhythmBox.
I'm using Music Playing Deamon, and created the following little script (called it songname) which will do as the second comment line says:
#!/bin/bash
# Prints out currently playing artist/songname or [none]
mpc | (
read s; read t; # read first two lines: song info and status
if [[ "${t:0:9}" == "[playing]" ]]; then
echo $s;
else
echo "[none]"
fi
)
