Album Art Fixer
There have quite a few useful audio utilities surfacing lately, one of those being the Album Art Fixer. While this utility can be used to add cover art for any media player it is targeted at MCE and WMP users. Album Art Fixer scans your audio files and then determines what needs to be "fixed", it gives you the option of fixing the cover art, album title, location and most importantly the album artist tag. Without an Album Artist tag your audio files will not display correctly in MCE.
The Thomas Hawk Digital Connection has done a great review of Album Art Fixer that is worth checking out.