refbase is a Web-based bibliographic manager that can import and export references in various formats (including BibTeX, Endnote, ISI, RIS, PubMed, MODS XML, OpenOffice, and Word 2007 XML). It can make formatted lists of citations in HTML, RTF, PDF, or LaTeX, and offers powerful searching and RSS support. Its OpenSearch and SRU/W services and support for unAPI and COinS metadata allow for easy access by clients and search engines.
Aigaion is a Web-based shared bibliography manager built on PHP/MySQL. It is based on the BibTeX format, but has support for other formats as well. Some of its key features are extensive support for organizing a bibliography in a topic structure, personal and public annotations on each publication, multi-user support, easy import/export, and an intuitive user interface.