Conference Management systems are web applications designed to make the lives of conference organisers easier. They usually include features such as registration, payment, paper submission and review, scheduling and publishing of announcements.

Since Wikipedia is apparently not a place for such a "spammy list," I figured I should at least post this here:

NameUsed byLicenseProgramming Language
A Conference ToolkitYAPC::EuArtistic LicensePerl
ConManUtah Open Source Conference, Texax Linux FestGPLPython (Django)
Open Conference Systemsvarious academic conferencesGPLPHP
OpenConferenceWareOpen Source BridgeMITRuby on Rails
PentabarfDebConf, FOSDEM, CCCGPLRuby on Rails
SCALEregSCALEGPLPython (Django)
Zookeeprlinux.conf.auGPLPython (Pylons)

If you know of any other Open Source systems, please leave a comment!

The Linux Plumbers Conference used something that worked out really well, and I don't think you have it on your list. I don't happen to know the name of the software though.
Comment by Anonymous

There's indico: http://cdsware.cern.ch/indico/index.html

We managed to make it work for EuroPython 2006 or so...

Comment by Michael Hudson-Doyle

I started in 2003 to write «Comas», originally as an Apache (mod_perl) module. After some four years, aiming at a much higher flexibility regarding the database schema, I rewrote it in Ruby on Rails.

I have not done any real promotion to Comas — I know I use it on all of my Institute's activities, and know of a couple of South American conferences that have used it. My main reason for not doing any promotion is that –because of lack of time, and because my Institute's needs are covered without this module– the submission rating and scheduling interface are still non-existant — Although they are planned and should see the light soon!

The project's website is http://www.comas-code.org/, and the git repository can be cloned at git://github.com/gwolf/comas.git

Comment by Gunnar
Cafuego and I are working on a Drupal based system.
Comment by KatteKrab

http://www.cs.ucla.edu/~kohler/hotcrp/

is used by a number of system conferences.

Comment by Reinhard Tartler

Thank for this list. Could you add this one: conf2py

http://code.google.com/p/conf2py/

thanks

Comment by Max
COD (Conference Organizing Distribution) is built on Drupal 6 (version for 7 is next). See usecod.com for more info.
Comment by Lisa Rex
Hi, great list. I re-added your list to the Wikipedia article after I have seen that -nothing- on that article happened after the deletion one year ago. Let's see...
Comment by digisus
Well stuff. include CDS Indico http://indico-software.org/
Comment by Anil JHA