Most of my work with queuing systems has been mostly expanding on existing systems. When I saw a meetup on RabbitMQ, I was extremely interested and I made it to pivotal labs. I even managed to play ping pong there for some time.
Alvaro is co-author of “RabbitMQ in action” and also maintainer of rabbitmq PHP client and a bunch of other open source libraries. The information was great – right from why you need messaging systems, what are queues, consumers, producers and how to implement them. You can view the slides here – introduction to rabbitmq.
Also, rabbit mq simulator is a great tool to visualize messaging.