ESB Resources

WikiPedia Page: http://en.wikipedia.org/wiki/Enterprise_service_bus

ServiceMix

JBI

http://www.theserverside.com/tt/articles/article.tss?l=JBIforSOA

FUSE

http://fusesource.com/products/

http://java.dzone.com/articles/fuse-esb-4-osgi-based