The primary means of communication in the Nebula community is the discussion list.
Bug Reports
Discussion and SVN Notification Lists
http://sourceforge.net/mail/?group_id=7192
The lists are also available for online browsing via Gmane and Nable
http://dir.gmane.org/index.php?prefix=gmane.comp.graphics.nebuladevice
http://www.nabble.com/The-Nebula-Device-f3433.html
IRC channel
nebula on irc.freenode.net
While IRC works well for quickly solving a problem, long discussions on design issues, bugs, or other important topics should likely happen on the mailing list.