Thanks so much for bringing my favourite Music organizing software to mobile devices (I use foobar2000 since ~2001). To definitely replace all my other music players on the iPhone i'd love to have the option to automatically download album art from the internet and store it in an internal database (only if no album art is already in the tags or folder of course). Such an automated download can be found in the iOS music player software "tuneshell".
This would save many people a lot of time when they do not have to mess around with album art :-) in tags.
Maybe this method would also be appliable to the android and Windows mobile port. Keep up the great work!