More information can be found from the event press release:
Open Source CMS Conference 4
ETH Zurich, Switzerland
Wed, Sept. 29th - Fri, Oct. 1st, 2004
OSCOM is proud to announce that registration for OSCOM.4 is now open, at $500 for three days. OSCOM.4 is a conference on open source content management with assistance from the Apache Software Foundation for the ApacheTrack content.
Disclaimer: I'm member of the OSCOM 4 organizing committee.