Library and/or book catalog setup with ISBN import

Is there a sensible set of modules which helps in constructing a library and/or book catalog site? One of the key features of this site would have to be a way to input book information on the basis of the ISBN, i.e. a user wanting to add a book would only have to fill in the ISBN, and some module would then log on to a major library (say, Library of Congress) to fetch all required information. My guess is this would have to be done on the basis of MARC cards. In doing so, the cataloger would only have to type the ISBN and not the tedious bulk of bibliographic information. So, basically, I guess I'm looking for a module (or combination) which knows how to handle ISBN numbers and which knows how to collect information from the major MARC-based catalogs of the world. This is the way www.librarything.com works. Any information would be welcome.