UPC Converter?

I've almost completed my catalog of graphic novels and trade paper backs (since i got my :Cuecat its been a breeze!), but i've run into the UPC problem: DC Comics used UPC codes and nothing else in the 90s and early 2000s (they actually might still do it) so i can't scan about 1/4th of my books. Entering them all by hand is a daunting task, and If i can find a work around it would be amazing.

I've searched around the site for a while, and there seems to be a few mentions of some way to convert UPC codes to ISBN if you have the right numbers... and since 90% of the problem codes are from the same publisher (DC) then i could easily get it.

Can anyone help me out with this? I really don't want to have to type all these in by hand. Thanks!

You might ask this on Talk about LibraryThing - it's not directly related to the CueCat and not many people read this group. I'll be interested to see if you get any answers...