Dealing with the Daylight Savings Time issue can be pretty confusing, especially since the tools and updates you need have been being made available over a period of time. Start with the Daylight Saving Time Help and Support Center. It gives you a centralized set of Microsoft's DST resources, including links to the updates for various products. From there, check out the following KB articles and updates especially pertinent for the Exchange admin:
- The first step is to apply the patches appropriate for your operating systems. Microsoft recommends applying the OS patches, applications patches, and running the update tools as close to the same time as possible. It would have been nice if they'd not been pushing the OS patches out via Windows Update; your servers and workstations may already have the patch installed.
- Update for daylight saving time changes in 2007 for Exchange 2003 -- apply this to your Exchange server to fix the issues in the Exchange program code, beyond what is covered by the OS patches.
- You can no longer mount any of the Exchange databases after you apply hotfix 926666 to a computer that is running Exchange Server 2003 -- this is a problem that some people have been reporting after applying the Exchange update. Apply this at the same time.
- How to address daylight saving time by using the Exchange Calendar Update Tool (for Exchange versions 2007, 2003, 2000, and 5.5) -- this tool is a server-side tool for adjusting appointments in the target date range. Read the KB thoroughly before using!
- Virtual Machine for Microsoft Exchange Calendar Update Tool -- this one is particularly cool if you have a large organization, because it allows you to quickly deploy multiple workstations with the Exchange Calendar Update Tool and provide coverage for all of your servers.
- How to address the daylight saving time changes in 2007 by using the Time Zone Data Update Tool for Microsoft Office Outlook (for Outlook versions 2000 through 2007) -- this is an alternative to the server-side tool, allowing users to go through and identify the appropriate appointments to be changed. This may be a better choice for your organization.
- Daylight Savings Time 2007 Update -- this page gives steps on updating your Windows Mobile device with the necessary updates.
- How to configure daylight saving time for the United States and Canada in 2007 and in subsequent years on Windows Mobile-based devices -- a KB article that explains the registry modifications necessary to update a Windows Mobile device if the previous update won't do the trick (see How to update daylight saving time for the United States, Canada, and Mexico in 2007 on Windows CE-based devices for the Windows CE version of the same guidance).
- Exchange Time Zone Update Tool: Guidance from Microsoft IT -- finally, a walkthrough from Microsoft IT showing how they dealt with this issue internally.
Unfortunately, the U.S. Congress really didn't do any favors for IT pros with the expanded DST timeframe. There's no magic bullet fix; you have a lot of updates to coordinate, a choice of tools to run, and a lot of opportunities to have appointments messed up even if you do everything right. Oh, and you don't have much time to figure it out. It doesn't help much to know that everyone is feeling your pain, but right now, that's the best I can offer you. That, and keep an eye out on the regular Exchange news sources and blogs; a lot of smart people are taking the plunge to figure out where the pain points are, and they're busily writing about it.
Hang in there.
Updated Feb 14 1430: I've added the Windows Mobile links to the list. Additionally, apparently many people with resource accounts (conference rooms, etc.) that are steadily booked are running into problems using the rebasing tools, because those accounts don't own the events and can't move them authoritatively. I'm aware of one potential workaround in the works for this and will point you to it as soon as I can.
Updated Feb 14 1610: Updated again with the link to the Exchange Time Zone Update Tool: Guidance from Microsoft IT paper.