As times have changed, our OPACs have not kept up. End-users want more from their library catalogs. They want the ability to create mash-ups with other services (e.g., LibraryThing), save catalog data in new and different ways (e.g., Zotero), and much, much easier findability (e.g., through faceted browsing.) As Eric Lease Morgan says, the next generation OPAC "design [is] less like a 'catalog' -- an inventory list -- and more like a finding aid." The resources listed below should get you started on what a Next Generation OPAC is, and who has been building and discussing them.