Visual Basic - always on top de una ventana en vb

como puedo hacer para que una ventana de un programa en vb este siempre visiblre, es decir, aunque yo selecciones otra ventana, la otra ventana nunca se va a desaparecer de la pantalla

En http://support.microsoft.com/support/kb/articles/q184/2/97.asp tienes la forma de hacerlo, se hace con:

Public Const SWP_NOMOVE = 2
Public Const SWP_NOSIZE = 1
Public Const FLAGS = SWP_NOMOVE Or SWP_NOSIZE
Public Const HWND_TOPMOST = -1
Public Const HWND_NOTOPMOST = -2
Declare Function SetWindowPos Lib "user32" Alias "SetWindowPos" _
(ByVal hwnd As Long, _
ByVal hWndInsertAfter As Long, _
ByVal x As Long, _
ByVal y As Long, _
ByVal cx As Long, _
ByVal cy As Long, _
ByVal wFlags As Long ) As Long
Public Function SetTopMostWindow(hwnd As Long, Topmost As Boolean) _
As Long
If Topmost = True Then 'Make the window topmost
SetTopMostWindow = SetWindowPos(hwnd, HWND_TOPMOST, 0, 0, 0, _
0, FLAGS)
Else
SetTopMostWindow = SetWindowPos(hwnd, HWND_NOTOPMOST, 0, 0, _
0, 0,FLAGS)
SetTopMostWindow = False
End If
End Function