A Supybot called bugbot is announcing all bugzilla.gnome.org changes in #bzbot on irc.gnome.org. However, if you want to have it announce just the changes for your product in some channel, please contact either me (GimpNet, #bugs) or mkanat (usually on irc.mozilla.org in #supybot — currently on gimpnet as well). For GimpNet, bugbot replaces the bots bzbot and bugsbot.
Bugzilla installations wanting such an announcement bot, just contact mkanat. If you want the plugin for your own Supybot, just run:
bzr co http://bzr.everythingsolved.com/supybot/Bugzilla
to check it out using bzr.