The JBoss SOA early adopter Swedish Railroad has been blogged about here earlier. Matt Asay picks up on this deployment more recently here.
Additionally, I presented Open Source SOA Value and Strategy at Red Hat Summit and SOA World in late June. CIO e-magazine picked up on the Swedish RR example and other current status of open source SOA and future projections here. In particular, we see the convergence of EAI, SOA, BPM, EDA and CEP into a set of integration styles that may be implemented using a common platform - the 2nd generation ESB or SOA Platform. A flexible platform like this is a more cost effective and simpler (reduced to no need for separate architectural bases for EAI, SOA, EDA, BPM, etc...) way to implement an agile IT and enterprise in the future.