Detecting Daylight Savings Time

I need to write VBA code that detects when Windows adjusts a computers clock for Daylight Savings Time. Or weather Daylight Savings Time is "On" or "Off".

Is there a method of retriving this information from WIndows?

The operating system is Windows XP SP 2

 

FYI: I posted the same question on the MSDN Forums and here are some of the information posted there
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I have found this in the registry:
HKEY_LOCAL_MACHINE\SYSTEM\ControlSet001\Control\TimeZoneInformation
ActiveTimeBias REG_DWORD 0x00000168(360)
Bias REG_DWORD 0x00000168(360)
DaylightBias REG_DWORD oxffffffc4(4294967236)
DaylightName REG_SZ Central Daylight Time
DaylightStart REG_BINARY 00 00 03 00 02 00 02 00 00 00 00 00 00 00 00 00
StandardBias REG_DWORD 0x00000000 (0)
StandardName REG_SZ Central Standard Time
StandardStart REG_BINARY 00 00 0b 00 01 00 02 00 00 00 00 00 00 00 00 00

U.S. Daylight Saving Time Schedule
2007: March 11 - Nov. 4
2008: March 9 - Nov. 2
2009: March 8 - Nov. 1
2010: March 14 - Nov. 7
2011: March 13 - Nov. 6

Therefore it appears to me that registry key is read as follows:
DaylightStart REG_BINARY 00 00 03 00 02 00 02 00 00 00 00 00 00 00 00 00
03 = March
02 = Second Sunday?
02 = 2am

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This web site might help:

http://www.netadmintools.com/art575.html


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How about .IsDaylightSavingsTime of the Date object:

http://msdn.microsoft.com/en-us/library/system.datetime.isdaylightsavingtime.aspx

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If you want to know about the machine the code is running on, and assuming the time is correct then, as stephen said use IsDaylightSavingTime. it should be available in most Microsoft languages.
Dim isDST As Boolean
isDST = DateTime.Parse("7/29/2009").IsDaylightSavingTime
isDST = DateTime.Now.IsDaylightSavingTime
'or
If DateTime.Parse("7/29/2009").IsDaylightSavingTime Then
'is DST
Else
'not DST
End If