Use Microsoft Message Queuing in C# for inter-process communication
Source: Zach Smith
Microsoft Message Queuing (MSMQ) is a way to send messages to a queue for later processing. The messages are sent to the queue by a "Producer" application, and retrieved from the queue by a "Consumer" application. These two applications can be on the same machine, across a network, or even on different machines that aren't always connected. Zach Smith demonstrates how to use Microsoft Message Queuing (MSMQ) for inter-process communication between applications on the same machine, or over the network. The download includes a project file containing all the sample code you need to read or write messages from a queue.
This download is also available as a TechRepublic article.