Two articles have been released to discuss the daylight saving time change and the impact on WSS:

933738 - An update is available that addresses an issue in which items that use the Date field and the Time field are off by one hour in Windows SharePoint Services
http://support.microsoft.com/default.aspx?scid=kb;EN-US;933738

933853 - How to manually update the TIMEZONE.XML file to be DST 2007-compliant if you cannot install update 924881 or a later update for Windows SharePoint Services software
http://support.microsoft.com/default.aspx?scid=kb;EN-US;933853