Messaging

• RabbitMQ?

Robust messaging for applications
Easy to use
Runs on all major operating systems
Supports a huge number of developer platforms
Open source and commercially supported
http://www.rabbitmq.com/

• zeromq

The socket library that acts as a concurrency framework.
Faster than TCP, for clustered products and supercomputing.
Carries messages across inproc, IPC, TCP, and multicast.
http://www.zeromq.org/

• Apache ActiveMQ

Apache ActiveMQ ™ is the most popular and powerful open source messaging and Integration Patterns server.
http://activemq.apache.org/