To be posted to the Microsoft Daylight Saving Time & Time Zone Hot Topics page at http://support.microsoft.com/gp/dst_hottopics...
Brazil 2007-2008 Daylight Saving changes: The government of Brazil announced a change on September 20, 2007, in the observance of daylight saving time in the country. The new time change will take place in Brazil on October 14th (three weeks earlier than in 2006) when clocks should move one hour forward at midnight (between Saturday and Sunday). On February 17, 2008, Brazil will move clocks one hour at midnight (again, between Saturday and Sunday), one week earlier than in 2006.
Microsoft has provided a hotfix update for customers requiring an update for this time change: for more information and to obtain the hotfix, please see Microsoft Knowledge Base article 943000.
Manual remediation has been provided for Windows as noted in KB article 914387, updated with the proper registry keys to account for the changes in Brazil; “Dynamic DST” keys are included allowing calendar rebasing with the Outlook Time Zone Data Update Tool (TZDUT).