Aigaion is a php/mysql based multi-user system for managing annotated bibliographies. It allows the user(s) to order publications in a self-chosen (overlapping) topic structure, offers BibTex and RIS import and export and has an intuitive user interface.
Currently looking for contributors and co-maintainer(s) to handle planned upcoming releases. Check http://www.aigaion.de for more.
Support and Documentation can be found at http://www.aigaion.de.