Iterating quickly through Outlook appointment items

You can use Restrict to filter. Note that dates are in the format month, day, year and that they are filtered as strings, even though stored as dates:

Set olApp = CreateObject("Outlook.Application")
Set olNS = olApp.GetNamespace("MAPI")

Set olRecItems = olNS.GetDefaultFolder(olFolderTasks)
strFilter = "[DueDate] > '1/15/2009'"
Set olFilterRecItems = olRecItems.Items.Restrict(strFilter)


For i = 1 To olFilterRecItems.Count
  <...>

More information: http://msdn.microsoft.com/en-us/library/bb220369.aspx