RabbitMQ for beginners explains what RabbitMQ and message queuing is. It gives a brief understanding of messaging and important RabbitMQ concepts are explained.
Federation has several use-cases; collect messages from multiple clusters to a central cluster, distribute load of one queue to multiple other clusters and when migrating to another cluster without stopping all producers/consumers while doing so.
This blog article explains what Message Queuing is, how it can be used and benefits achieved when using Message Queues.
Get started with RabbitMQ on Android! Create a simple chat room in Android (Eclipse), using RabbitMQ