The Microsoft Agent Control
The home of the Microsoft Agent Control. It provides all information concerning the interface.
http://msdn.microsoft.com/library/default.asp?url=/library/en-us/msagent/agentstartpage_7gdh.asp

TCC Publishing
Provides the Microsoft Agent Control as installabe .exe file and the Microsoft own Agents.
http://tcc-pub.com/agents/agents.htm

The Microsoft Agent Ring
The Microsoft Agent Ring is a bunch of websites covering different aspects of the topic Microsoft Agent Control.
http://www.msagentring.org/

Eclipse Agentry
The home of the Eclipse Agentry. Here you get the sources and binaries.
http://sourceforge.net/projects/eclipseagentry/