SAFMQ: Store and Forward Message Queue, message oriented middleware. Uses include Assured Async Messaging, SOA, Delayed/Batch, and Cluster/Grid Computing. The SAFMQ server provides cross platform communication among C++, PHP, Java, and .NET clients.
WritTorrent - Rewriting BitTorrent distribution by providing a way to manage swarm topology using RSS. We're in the initial stages of providing basic utilities for the most flexible handling of .torrent files through xml syndication technologies.
OpenRMI defines a messaging interface. This interface is applied in a one to many fashion, using a controller with many nodes. The nodes connect via RMI to the controller and are assigned work via the same interface.