In addition to the quarterly-issued Pitcairn Log, auctions, and a variety of web-based interactions, there are in-person PISG events. These events usually occur at international philatelic exhibitions (the next PISG event at an international is scheduled for New York 2016 to be held in New York City at the end of May 2016).
There will also be a PISG meeting, in conjuction with a larger convention of British areas, at St. Louis Stamp Expo 2014 on March 21-23, 2014.
Recently PISG sponsored the Bounty-Pitcairn Conference 2012 at the Pitcairn Islands Study Center at Pacific Union College at Angwin in California's Napa Valley region from August 19-21, 2012.
PISG elections are also held every two years. The next election is scheduled for Spring 2015. See results of the 2013 elections here.