I'm sure many of you are already familiar with OCLC's xISBN service.
Today I released "thingISBN," LibraryThing's "answer" to xISBN. Where
xISBN uses OCLC's FRBRized data, thingISBN uses LibraryThing's
"everyone a librarian" wiki-like cataloging. The results are pretty
interesting, I think. xISBN has better coverage and I suspect makes
fewer mistakes, but thingISBN is  strong on paperbacks and non-US
editions. There's a way of asking it to compare the two, so you can
evaluate it yourself.

Like xISBN, it's free for non-commercial use. It follows the xISBN XML
format, so it can be plugged into existing code quite easily. I'm
interested to see if anyone does anything interesting with it.

I blog about the service here

Comments, of course, appreciated. And for what it's worth I'm still
looking for a crackerjack library programmer...