Source Configuration Management

Aegis
A transaction-based SCM system, providing a framework for a team of developers to work on changes to a program independently, and then integrating these changes back into the master source. Open Source.
http://aegis.sourceforge.net/

Chicago Interface Group, Inc. (CIG)
CIG specializes in change management and systems integration solutions that allow companies to standardize configuration management throughout the enterprise. Use CA-Endevor or IBM's SCLM enterprise-wide.
http://www.cigi.net

NXN alienbrain
Cross-platform configuration management/version control system for any type of data. Optimized for computer graphics projects. (commercial)
http://www.nxn-software.com/

Parrus
Provides companies with SCM solutions and products.
http://www.parrus.com/

PrimeCode/RMS
A Software Configuration Management (SMC) tool for the HP NonStop Platform. PrimeCode/RMS manages changes to software applications through the entire software life cycle.
http://www.emperex.com/

Seapine Software
Surround SCM, by Seapine Software, is a cross-platform solution with client and server support on Microsoft Windows, Linux, Solaris, and Mac OS X operating systems. (commercial)
http://www.seapine.com/sourcecontrol.html

Serena Version Manager
Software configuration management (SCM) tools including version manager, tracker, configuration builder, replicator and SCM2000.
http://www.serena.com/

Source Code Manager
A configuration management tool for managing the source of projects especially multi-programmer projects, tracking revisions to the entire software system and making all releases consistent across the programming team.
http://www.unipress.com/

WANdisco
The WANdisco SCM suite comprises of multi-site SCM solutions for CVS, CVSNT, and Subversion. It aims to allow a development team to be spread-out across the world and work as one unit.
http://www.wandisco.com/