NCSA Habanero
- framework designed to give developers the tools they need to create collaborative Java applications. The framework provides the necessary methods that make it possible to create or transition existing applications and applets into collaborative applicati
- http://www.isrl.uiuc.edu/isaac/Habanero/

Collaborative Virtual Workspace
- A collaboration software environment that provides a "virtual building" where teams can communicate, collaborate, and share information, regardless of their geographic location.
- http://cvw.sourceforge.net/

CCF (Collaborative Computing Frameworks)
- A suite of software systems, communications protocols, and tools that enable collaborative work for natural sciences research, "collaboratories".
- http://www.mathcs.emory.edu/ccf/

Yoga
- free software workalike of Lotus Notes
- http://samba.anu.edu.au/gnuotes/