DSpace - DSpace open source software enables open sharing of content that spans organizations, continents...
Koha - Koha is the first free and open source software library automation package (ILS).
Greenstone Digital Library - Greenstone is a suite of software tools for building and distributing digital library collections...
TinyCat - The online catalog and integrated library system for tiny libraries, powered by LibraryThing.
Evergreen ILS - Evergreen - Open Source Library Software
Omeka - Omeka is a free, flexible, and open source web-publishing platform for the display of library, museum, archives, and scholarly collections and exhibitions.