I just found this:
an "Open conference system" from the Public Knowledge Project. It
might be worth checking out for Wikimania '08.
" Open Conference Systems (OCS) is a free Web publishing tool that
will create a complete Web presence for your scholarly conference...."
* create a conference Web site
* compose and send a call for papers
* electronically accept paper and abstract submissions
* allow paper submitters to edit their work
* post conference proceedings and papers in a searchable format
* post, if you wish, the original data sets
* register participants
* integrate post-conference online discussions
OCS version 2.0 is now available. New features include:
* manage conferences that occur more than once (e.g. yearly)
* an expanded, multiple-round review system
* e-mail template system
* localization & translation tools
* credit card payment for registrations
* automated "thanks-for-submitting" messages
* accept login/password for participants
* Creative Commons licensing of presentations
* more customizable, scalable and secure code
* ...and much more.