To make this board show correct times during daylight saving, edit your timezone setting in your profile:
All on the East Coast, change it from "GMT+10" to "GMT+11".
Other just add an hour to your current setting.
Update for phpBB3
Got to the "board preferences" page in the UCP ( ucp.php?i=165 )
Make sure your timezone is set correctly (UTC+10 for all the east coast),
then just set "Summer Time/DST is in effect:" to "yes" or "no" as appropriate.