We do all our scheduling through VORC: volunteers.rollercon.com. If you're not in there yet, please go create a login and request Announcer Department (and any other you're interested in).
Shifts are uploaded in June, and an announcement made on the volunteers FB group. You may self-select shifts, usually only 2 per day to start, but more if they are available closer to RollerCon.
Almost every shift can be self-selected for specific bouts, which are scheduled by Announcing Management using this form you are looking at right this MINUTE.
Thanks for volunteering for RollerCon!!
Find out more about volunteering, including compensation and more:
http://rollercon.com/help-wanted/