Google Book Search Adds "Find It At The Library" Link

The Google Book Search blog announced a feature named "Find this book in a library." How does it work? I went to a book and clicked on the Find this book in a library, which takes you to the OCLC Worldcat. Then you type in your postal code, state, province or country. I entered in a NYC zip code, 10010 into the search box. Then I clicked on the first result and ended up at this page that showed me that the status is available. More details at Google Book Search Help Center.