I found a program the other day called TuneUp that fixes all the song information (track title, album title & album art) for all your music in iTunes. I only tried the free 100 song version as I have already done most of my by hand now. But for the few albums I did do, it seemed to work reasonably well.
Although I didn’t get one album wrong. Unfortnatuly I didn’t realise this until after I had let iTunes change the album title. Oh well.