I am running Outlook 2003 SP2.  Under Tools > Options I have Default Reminder
checked and set to 15 minutes.  One thing that seems to differ from what I
remember of previous versions of Outlook is that invites automatically go to
my calendar when I receive them regardless of whether or not I have
accepted/declined them.  Could that have something to do with it?  Any way to
turn off that behavior?  

Here is the code with the necessary modification
--------------------------------------------------------------------------------
Private WithEvents Items As Outlook.Items

Private Sub Application_Startup()
 Dim Ns As Outlook.NameSpace

 Set Ns = Application.GetNamespace("MAPI")
 Set Items = Ns.GetDefaultFolder(olFolderInbox).Items
End Sub

Private Sub Items_ItemAdd(ByVal Item As Object)
 On Error Resume Next
 Dim Meet As Outlook.MeetingItem
 Dim Appt As Outlook.AppointmentItem

 If TypeOf Item Is Outlook.MeetingItem Then
   Set Meet = Item

   Meet.ReminderSet = True
   Meet.ReminderMinutesBeforeStart = 15
   Meet.Save

   Set Appt = Meet.GetAssociatedAppointment(True)

   If Not Appt Is Nothing Then
     Appt.ReminderSet = True
     Appt.ReminderMinutesBeforeStart = 15
     Appt.Save
   End If
 End If
End Su
--------------------------------------------------------------------------------

Go into Tools->Macros->Visual Basic Editor and then cut and paste the above
code.

Sean