This example inserts a movie named "Clock.avi" onto slide one in the active presentation, sets it to play automatically after the slide transition, and specifies that the movie object be hidden during a slide show except when it's playing.
With ActivePresentation.Slides(1).Shapes.AddOLEObject(Left:=10, _
Top:=10, Width:=250, Height:=250, _
FileName:="c:\winnt\clock.avi")
With .AnimationSettings.PlaySettings
.PlayOnEntry = True
.HideWhileNotPlaying = True
End With
End With