The Org-Mode Manual section on Deadlines and scheduling shows that you can set item-specific lead-times on the warnings for
DEADLINE:. Lead-time is how many days before the date it will appear in your Agenda to warn you of the upcoming task.
Setting your timestamp to
<Scheduled Date -0d> or
<Deadline Date -0d> will set the warning lead-time to 0 days. This ensures that it will not show up until the day the timestamp indicates. Overdue items will continue to appear until marked done.
Two things to note:
This will not hide the TODO item from the Agenda TODO list obtained used
C-c a t (List of all TODO entries).
If you complete a task before the
SCHEDULED: date (For example you complete it on [2011-11-22] and it is
SCHEDULED: for [2011-11-25]), it will still show up on the
SCHEDULED: date if
org-agenda-skip-scheduled-if-done is set to
nil. To prevent this behaviour you have to set the following:
(setq org-agenda-skip-scheduled-if-done t)