Currently Being ModeratedSep 11, 2012 2:27 PM (in response to Lee Bergamini)
iCal has a "Time Zone Support" option in the app preferences, if it is on try switching it off, or vice versa and see if that changes things. The Mac knows whether it needs to be daylight saving time or not based on the date, that's why it doesn't have the option in time settings.
Currently Being ModeratedSep 11, 2012 9:43 PM (in response to Lee Bergamini)
There is also an automatic time zone setting based on location in System Prefernece/Date & Time/Time Zone.
If you have an iMac and a MacBook have you compared time settings in both system preferences and the calendar to confirm both computers are set up the same?