The CoverFlow graphic interface is certainly a nice tool to browse your albums, either in your Apple handheld (iPod Touch, iPhone) or on iTunes itself. But it doesn't look that cool when most of your album covers are missing, does it?
iArtWork can fix this problem for you. This iTunes add-on searches for covers for all the albums in your iTunes library. The only requirement for this little app to work is that you have your music properly tagged, as these tags are the keywords iArtWork uses to look for covers on the Internet.
Found covers are displayed on the program's interface, from where you can import them directly into iTunes. In case there's more than one cover available for the same album and you want to change the one that iArtWork has chosen, double click on the album title and a Search tool will open up. From this same tool you can also search for new covers that the program hasn't been able to find, though most of the times it won't be necessary.
With iArtWork you'll be able to fill in the visual gaps in CoverFlow, provided that you have your music collection perfectly tagged.