Apache Qpid

Qpid provides multiple language implementations of the Advanced Messaged Queuing Protocol (AMQP) specification and related technologies including transaction management, queuing, distribution, security, management and heterogeneous multi-platform support for messaging. Qpid's overall goal is to create an open and interoperable implementation for messaging which implements the AMQP specification. Currently there is a Java and C++ broker with clients in C++, Java (JMS), Ruby, Pyhton and C# for .NET

http://cwiki.apache.org/qpid/