TuneWiki also has a built-in Album Art function.
Within TuneWiki : Menu -> Album Art Manager.. then Menu -> Fetch.
If you see lots of Album Art in your Gallery afterwards, you'll have to go through your Music folder and remove the files that have "AlbumArt" in the name ... Prior to removing, you should make sure that in that same folder, there is a file called "folder.jpg" which will be the album art used by the Music Player. I believe the other "AlbumArt" files are there simply as different resolution images ... all they do for me is clutter up the gallery.