Pieced together a bunch of scripts out there for improving pianobar.

PianobarGrowlScrobbler.sh

#!/bin/bash

# create variables
while read L; do
	k="`echo "$L" | cut -d '=' -f 1`"
	v="`echo "$L" | cut -d '=' -f 2`"
	export "$k=$v"
done < <(grep -e '^\(title\|artist\|album\|stationName\|pRet\|pRetStr\|wRet\|wRetStr\|songDuration\|songPlayed\|rating\|coverArt\)=' /dev/stdin)

case "$1" in
	# React when the song changes
	songstart)
	# Since $rating is a number, we translate it into a heart if the user likes the song or
	# not.
		if [ $rating -eq 1 ]
		then
			heart="<3"
		else
			heart=""
		fi
		
		# This makes sure the directory for storing the album art exists

		if [ ! -d ~/.config/pianobar/art ] 
		then
			mkdir ~/.config/pianobar/art
		fi
		if [ ! -d ~/.config/pianobar/art_archive ] 
		then
			mkdir ~/.config/pianobar/art_archive
		fi
		# Change to the album art directory
		cd ~/.config/pianobar/art
		# Get rid of any existing album art, but don't complain if there isn't any
		# ...actually i kinda want to accumulate it...
		# rm * 2> /dev/null
		mv * ~/.config/pianobar/art_archive 2> /dev/null

		# $coverArt is a URL pointing to the album art, so download it

		wget -q "$coverArt"

		# Finally, show the notification with the title, artist, album name, heart icon, and
		# album art image. We set the identifier (with the -d switch) to make all of the
		# notifications show in one bubble.
		echo "\"$title\" by \"$artist\" on \"$album\" $heart" | growlnotify -n "pianobar" --image * -d 12 pianobar
	;;
	songfinish)
		# scrobble if 75% of song have been played, but only if the song hasn't
		# been banned
		if [ -n "$songDuration" ] &&
				[ $(echo "scale=4; ($songPlayed/$songDuration*100)>50" | bc) -eq 1 ] &&
				[ "$rating" -ne 2 ]; then
			# scrobbler-helper is part of the Audio::Scrobble package at cpan
			# "pia" is the last.fm client identifier of "pianobar", don't use
			# it for anything else, please
			scrobbler-helper -P pia -V 1.0 "$title" "$artist" "$album" "" "" "" "$((songDuration/1000))" &
		fi
		;;
esac