Flutterby™! :

Oh, to follow up my comments about XML-RPC, I suppose I ought to put up or shut up and post some code. Here's a Perl fragment to get book info from Barnes & Noble, Amazon and Borders. Run it in a directory with a file called "isbn", one number per line. It's not massively smart, there are a few problems, and some interesting issues show up in the database differences between those three samples, but it's a quick hack to play with some data reaping ideas and learn a bit more about good ways to extract data.