Active Zope 2, Zope3, and Zope Toolkit developers should subscribe to the zope-dev mailing list.
Developers who work actively on the zope2 Launchpad project should either subscribe to the zope2-tracker notifications mailing list (this list receives notifications from Launchpad for each updated issue in the zope2 project), or ask to be added to the zope2-dev team on Launchpad.
Grok developers should subscribe to the grok-dev mailing list.
BlueBream developers should subscribe to the bluebream mailing list.
Depending on your interest you can subscribe to other Zope mailing lists as well:
http://mail.zope.org/mailman/listinfo