i also use itunes agent, but it's limitations are that it cannot truely transfer itunes playlists onto the device. so all the customization that you made to your tags/playlists cannot be transferred.
you create a playlist in itunes where you will put all the music you want to go to the phone, then use itunes agent to transfer the music. but once on the device, if you want to reproduce your customized play orders/playlists, you will need to do that manually on the device. in order to play an album in correct track order you must be in album view, long press on the album and press play.
lastly, go to the market and get yourself cover art downloader, it will get all the artwork that doesn't appear automatically.
when compared to an ipod, android phones are lacking, but so far it's good enough for me. maybe someone will come forth with a better app or software to integrate playlists and extended metadata supported by itunes/ipods.
EDIT: tunesync can do what you're looking for, but it's a paid app. i wouldn't mind spending the 5$ because it copies the playlist verbatim with album art, and can do it via wifi.
