- Create tab labeled "Volunteers," appearing after "Online Registration" tab
- Update "Configure" action link menu with direct link to this tab
- Create form (and form handling logic) for en-/disabling volunteer management.
- Disable three links/buttons for volunteer management when enabled for the event.
- Each of these three task links should also be injected the "Event Links" button menu.
See http://wiki.civicrm.org/confluence/display/CRM/CiviVolunteer+dev+notes#CiviVolunteerdevnotes-VolunteersTab for more detail.