Looking for information on the virtual libraries collaborating in Second Life through Alliance Virtual Library? The Alliance Virtual Libraries Catalog provides slurls (Second Life url addresses) that will take you to many inworld libraries and library related sims. Another directory lists many of the libraries and projects on Info Island.
(Note: I revisit this blogpost in 2020 and although Alliance Virtual Libraries is no longer active, the Community Virtual Library expanded on the work of early adopters and kept virtual world librarianship alive.)