Nel generale del form mettete questo: 
Private Declare Function SetWindowPos Lib "user32.dll" (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
Private Const HWND_TOP As Long = 0
Private Const HWND_TOPMOST As Long = -1
Private Const HWND_NOTOPMOST As Long = -2
Private Const SWP_NOMOVE As Long = &H2
Private Const SWP_NOSIZE  As Long = &H1


Per far diventare form in primo piano: 
SetWindowPos Form1.hwnd, HWND_TOPMOST, 0, 0, 0, 0, SWP_NOMOVE + SWP_NOSIZE