BibDesk is a bibliographic reference manager for Mac OS X. BibDesk is designed to help organize and use bibliographic databases in BibTeX .bib format. In addition to manual typing, BibDesk lets you drag & drop or cut & paste .bib files into the bibliographic database and automatically opens files downloaded from PubMed. BibDesk also keeps track of electronic copies of literature on your computer and allows for searching your database through several keys.
BibDesk integrates well with TeX for creating citations and bibliographies. This integration includes a Citation search completion service, and drag & drop (cut & paste) support for adding citations to TeX files.
The biblatex package by Philipp Lehman is likely to become the definitive citation management tool for LaTeX users. Biblatex relies on the venerable BibTeX program only for sorting and generating a very generic bbl file without any formatting instruction. Everything else is taken care of by biblatex, which provides a powerful and flexible macro interface for authors of citation styles.