This courtesy of the WinMobile team.... (thanks, Chris!): instructions for Windows Mobile users who connect to a PC, and users who do not connect to their PC, on how to update your devices for the upcoming daylight saving time (DST ) changes after you have installed the Windows OS update for DST (KB 931836). You can install the update via Microsoft Update if you don't want to wait for it to install via Automatic Updates.
If you use Microsoft Outlook to synchronize your calendar, download and run the Outlook Time Zone Update Tool.
Here are the details on this Windows Mobile update:http://www.microsoft.com/windowsmobile/daylightsaving/default.mspx