Please keep in mind, that if it is not updated, all items which require a date time stamp reference will be out by 1 hour.
If necessary, time zone information for Sharepoint can be manually updated, as per the following KB:
This involves editing the timezone.xml file, located at
C:\Program Files\Common Files\Microsoft Shared\Web Server Extensions\12\CONFIG
In the following example, the end time for daylight savings is set to the first week in April, and the start time for daylight savings is set to the first week in October.
Note that the section refers to the week in the month. If this is set to 5, that means the last week.
<TimeZone ID="76" Name="(GMT+10:00) Canberra, Melbourne, Sydney" Hidden="FALSE"> <Bias>-600</Bias> <StandardTime> <Bias>0</Bias> <Date> <Month>4</Month> <Day>1</Day> <Hour>3</Hour> </Date> </StandardTime> <DaylightTime> <Bias>-60</Bias> <Date> <Month>10</Month> <Day>1</Day> <Hour>2</Hour> </Date> </DaylightTime> </TimeZone>