Google to WorldCat without username/password

Open WorldCat program [OCLC - WorldCat]

WorldCat update
WorldCat is the world’s most comprehensive bibliographic database. Updated at a rate of nearly one new record every 10 seconds, WorldCat contains more than 61 million bibliographic records and holdings information contributed by more than 8,600 libraries around the world. The Open WorldCat program makes the items in library collections—physical and digital, popular or special—discoverable by people searching the Internet.

[The Google toolbar can be configured to look up book information at Amazon, Alibris or WorldCat. Once you put your zip code in, it gives you the libraries in concentric order.]