The Compo Calendar has been around for some time already, but now it has been expanded to bring together people who like to compo from various different IRC networks.
For more information, take a peek at this:
http://www.modarchive.com/compost.pngThe Calendar Interface for quick-browsing the calendar via the web is available at:
http://compost.red-heat.com/This calendar is designed for tracker compos only.
To get your compo listed, you can PM me (m0d) on the forums, or ask any operator in #modarchive on irc.esper.net, OR if you're going to regularly post compos you can get your own posting account setup on IRC, again, contact me.
If you want more information, you can request the help function via IRC by joining #compost on either Espernet, Efnet or IRCnet and issuing the !compohelp command in the channel.