More on open-source ESB's

Note that most of these posts are old news (last year)
More on the integration between synapse, servicemix and celtix.:
Open-source projects intertwine for integration
http://news.com.com/2102-7344_3-5844789.html?tag=st.util.print

Open source's next frontier
http://news.com.com/Open+sources+next+frontier/2100-7344_3-5460334.html

and an opinion from a vendor (Capeclear)
Open Source and the ESB!
http://www.capeclear.com/annrai/archives/2005/08/open_source_and.html