As I previously noted, Venezuela is changing their time zone. We were able to confirm that Venezuela time zone has been confirmed to GMT -4:30 as original planned.
We now hear from government sources that the new DST change will begin Sept 24 (next Sunday) when at midnight clocks will move backwards 30 minutes. This will be a ½ hour change, from UTC-4:00 GMT to UTC-4:30.
It appears that this is the creation of a new time zone (as noted http://www.timeanddate.com/worldclock/timezone.html?n=58): to date, Venezuela observed AST, and now is essentially cretaing their own TZ as of September 24, 2007.
We don't know yet if this is a permanent change or if this is a move to their new DST.
We will have more information on this change at http://support.microsoft.com/gp/dst_hottopics, and we expect to have a Windows OS hotfix for currently supported products available prior to the change.