This example adds two rectangles to the first slide in the active presentation and connects them with a curved connector. Notice that the RerouteConnections method makes it irrelevant what values you supply for the ConnectionSite arguments used with the BeginConnect and EndConnect methods.
Set myDocument = ActivePresentation.Slides(1)
Set s = myDocument.Shapes
Set firstRect = s.AddShape(msoShapeRectangle, 100, 50, 200, 100)
Set secondRect = s.AddShape(msoShapeRectangle, 300, 300, 200, 100)
With s.AddConnector(msoConnectorCurve, 0, 0, 100, 100) _
.ConnectorFormat
.BeginConnect ConnectedShape:=firstRect, ConnectionSite:=1
.EndConnect ConnectedShape:=secondRect, ConnectionSite:=1
.Parent.RerouteConnections
End With