As I mentioned six months ago, one of the big things in the library world is FRBR which seeks to link all editions of the same book together. The OCLC offers their take on it as a web service called xISBN, and LibraryThing does something similar with thingISBN. Back in March, I wrote about how a hidden feature in Amazon's API does something similar and can be used as a third public service for that type of information.
Sometime in the summer, I found a fourth public service that offers something similar - Google Book Search. There is a special search operator called "editions" which can be used to lookup all editions of a given ISBN. For for the canonical Dune example, one would type in "editions:ISBN0441172717" in Google Book Search and voila, out come the results! Of course, using their Book API makes it easier.
I added this as a fourth service to my BookChaser Editions tool.