Implementing a Message Bus architecture

the Apache ActiveMQ (open source) message broker also has a .NET client:

http://activemq.apache.org

Together with Apache Camel and Apache ServiceMix, enterprise integration patterns and enterprise service bus systems are easy to set up.

IMHO, with so many good, flexible and proven bus architectures to choose from (NServiceBus, Mass Transit, Rhino Service Bus), implementing your own would be a big NIH. It's not a trivial task.

Udi describes it very well in this message.

Sorry, coming very late to this, but hopefully my answer is useful for MSMQ 4.0 users (but not necessarily useful to users of later versions).

Both WCF Queuing and System.Messaging are wrappers over the MSMQ APIs. WCF is more sophisticated and complex, but does have the following benefits:

• An OO view of your application's business processes rather than its communication plumbing.
• End-to-end message encryption and authentication for free. System.Messaging only supports encryption on the wire, not in the store.
• If you wish, you can host within IIS rather than building your own custom host.
• Message correlation for free. This allows you to group messages into sessions automatically.
• Transactional batching for free.