ActiveMessaging is an attempt to bring the simplicity and elegance of rails development to the world of messaging. Messaging, (or event-driven architecture) is widely used for enterprise integration, with frameworks such as Java's JMS, and products such as ActiveMQ, Tibco, IBM MQSeries, etc.

ActiveMessaging is a generic framework to ease using messaging, but is not tied to any particular messaging system - in fact, it now has support for Stomp, AMQP, beanstalk, Amazon Simple Queue Service (SQS), JMS (using StompConnect or direct on JRuby), WebSphere MQ, the all-Ruby ReliableMessaging, a mock 'test' adapter, and a 'synch' adapter for use in development that processes calls synchronously (of course) and so requires no broker or additional processes to be running.

Here's a sample of a processor class that handles incoming messages:

class HelloWorldProcessor < ActiveMessaging::Processor
	subscribes_to :hello_world
	def on_message(message)
		puts "received: " + message
	end
end

Best bet is the google groups mailing list:

http://groups.google.com/group/activemessaging-discuss