I've used this simple function to prevent resizing or allowing resizing. Depends what you want to do.
Code:
'in the declaration part of a form
Dim lngHeight, lngWidth As Long
'After the declarations
Private Sub Form_Resize()
    Resizer lngHeight, lngWidth 'Call the resize function
End Sub

Private Function Resizer(ByVal lngHi As Long, ByVal lngWid As Long)
If WindowState < 1 Or WindowState > 2 Then  'VB will call the resize event when minimizing
                                            'or Maximizing; you cannot resize a form in these
                                            'states, so skip
    Form1.Height = lngHi
    Form1.Width = lngWid
End If
You set the variables to whatever you want. Can prevent resizing, or you can add
more code to adjust the variables
to do anything you want. Has no recursive side-effects (that I know of!)