What software do I need in order to add JMS message passing to my enterprise's existing distributed applications?
The "J" in JMS stands for Java, so the first prerequisite is a Java development and runtime environment.
The second prerequisite is Java-based distributed applications, as opposed to C++/CORBA applications. Examples include applications developed using the distributed computing framework that accompanies popular Java application servers such as Gemstone/J, ObjectSpace's Voyager, the WebLogic server, and others. EJB applications are, of course, distributed applications. Enterprise JavaBeans are often deployed in EJB-only servers, or in EJB-capable Java application servers.