I've got several albums that amazon.com [or wherever] can't find the right cover too.  I do have the gif or jpg file with some of the missing covers, though.  Is there a way I can add this file to the ~/.kde/share/apps/amarok/* files?  I thought it would be fairly straightforeward but nope.  Same question for a lot of song lyrics?  I've done a grep -r but haven't found where the lyrics are stashed.  Clues, please, and thanks for a great set of well integrated programs!!

In Amaroki, rght-click the empty cover image and select "Assign cover"...
For lyrics, edit the track info.