This takes my playlists, managed by mpd, fixes them up, and places them in a staging folder, ready to sync with my Android phone. The script also asks if you'd like to sync the music after staging. Who needs iTunes anyway.

plsync.sh

#!/usr/bin/env zsh

# Takes all my playlists from ~/.mpd/playlists, fixes them up, and creates a
# folder for each, along with the music they reference.

# The sync stage requires an sshd server to run on your phone, as well as the rsync executable.
#   - http://linux.wxs.ro/2011/08/05/rsync-your-android/

MPD_MUSIC_ROOT="${HOME}/Music"			# Root of your MPD library
MPD_PLAYLIST_ROOT="${HOME}/.mpd/playlists"	# MPD playlist folder
SYNC_MUSIC_ROOT="${HOME}/Android/Sync/Music"	# Staging folder (receives all files prior to sync)
PLAYLIST_ROOT="${SYNC_MUSIC_ROOT}/playlists"	# Where to place playlist files (m3u) for sync
PHONE_MUSIC_ROOT="/sdcard/Music"		# Where the music will live on your phone
PHONE_ADDRESS="Nexus"				# Address to access your phone over ssh for sync

# Output stuff to stdout if $DEBUG evaluates to anything
# $ DEBUG=1 plsync.sh
function debug()
{
    [[ ! -z "$DEBUG" ]] && echo $*
}

# Sync stuff with phone over rsync+ssh
function sync() {
    rsync -vzrL --delete-after --no-perms --no-t ${SYNC_MUSIC_ROOT}/ ${PHONE_ADDRESS}:${PHONE_MUSIC_ROOT}/
}

# Ask for confirmation on something
function confirm()
{
    echo -n "$@ [y/N] "
    read answer
    for response in y Y yes YES Yes Sure sure SURE OK ok Ok kk; do
	[[ "_$answer" == "_$response" ]] && return 0
    done

    return 1
}

[[ ! -d "$PLAYLIST_ROOT" ]] && mkdir -p "$PLAYLIST_ROOT"

for pl in ~/.mpd/playlists/*.m3u; do
    plname="$(basename ${pl})"
    plname="${plname%%.*}"
    plfolder="${SYNC_MUSIC_ROOT}/${plname}"
    plfile="${PLAYLIST_ROOT}/${plname}.m3u"

    [[ -f "$plfile" ]] && rm -f "$plfile"
    [[ -d "$plfolder" ]] && rm -rf "$plfolder"
    [[ ! -d  "$plfolder" ]] && mkdir -p "$plfolder" && touch "$plfile"

    while read line; do
	f="${MPD_MUSIC_ROOT}/${line}"
	bn=$(basename "$f")

	if [[ -f "$f" && ! -f "${plfolder}/${bn}" ]]; then
	    ln -s "$f" "$plfolder"
	    echo "${PHONE_MUSIC_ROOT}/${plname}/${bn}" >> "$plfile"
	fi

    done < "$pl"
done

confirm "Would you like to sync with your phone? (Make sure sshd runs on the device)" && sync

How could I add a list of playlists to sync? Not every playlist should get synced. for pl in ~/.mpd/playlists/*.m3u; do?

You can define an array of playlist names you want to sync, and then check for those when you're iterating all of your playlists.
I modified my script to use bash instead, but this should also work in zsh.

I defined my set of playlists to synchronize similar to this:

# Array of playlist basenames to synchronize
syncpl=(workout cardio work minimal chill jungle)

Another more comfortable way to maintain the list might be to have a list in another text file and then read it, so you don't have to touch the script any time you want to add another playlist.

I then added a function to check whether a string is contained in an array, which I totally stole from stackoverflow:

# Check if an array contains a certain value
array_contains () {
    local seeking=$1; shift
    local in=1
    for element; do
        if [[ $element == $seeking ]]; then
            in=0
            break
        fi
    done
    return $in
}

Now in the for loop, after the basename of a playlist is determined, I can easily check if it is contained in the set of lists I want to synchronize:

# Jump to the next for loop iteration if we don't want to sync this playlist
array_contains "${plname}" "${syncpl[@]}" || continue

I hope you get the idea. It's probably best if you modify this script to fit your needs better, as did I.