在窗体系统菜单中加入自己的内容，使用subclass，占用资源。  
Option Explicit 

Declare Function AppendMenu Lib "user32" Alias _ 
"AppendMenuA" (ByVal hMenu As Long, ByVal wFlags _ 
As Long, ByVal wIDNewItem As Long, ByVal _ 
lpNewItem As String) As Long 

Declare Function GetSystemMenu Lib "user32" _ 
(ByVal hWnd As Long, ByVal bRevert As Long) As Long 
Declare Function SetWindowLong Lib "user32" _ 
Alias "SetWindowLongA" (ByVal hWnd As Long, _ 
ByVal nIndex As Long, ByVal dwNewLong As Long) As Long 

Declare Function CallWindowProc Lib "user32" _ 
Alias "CallWindowProcA" (ByVal lpPrevWndFunc _ 
As Long, ByVal hWnd As Long, ByVal Msg As _ 
Long, ByVal wParam As Long, ByVal lParam As Long) As Long 

Public Const WM_SYSCOMMAND = &H112 
Public Const MF_SEPARATOR = &H800& 
Public Const MF_STRING = &H0& 
Public Const GWL_WNDPROC = (-4) 
Public Const IDM_ABOUT As Long = 1010 
Public lProcOld As Long 

Public Function SysMenuHandler(ByVal hWnd _ 
As Long, ByVal iMsg As Long, ByVal wParam _ 
As Long, ByVal lParam As Long) As Long 
If iMsg = WM_SYSCOMMAND Then 
If wParam = IDM_ABOUT Then 
MsgBox "歪歪的VB小技巧第22天的技巧", vbInformation, "歪歪的VB技巧" 
Exit Function 
End If 
End If 
SysMenuHandler = CallWindowProc(lProcOld, _ 
hWnd, iMsg, wParam, lParam) 
End Function 

Public Function SubClass(FormName As Form) 
Dim lhSysMenu As Long, lRet As Long 

lhSysMenu = GetSystemMenu(FormName.hWnd, 0&) 
lRet = AppendMenu(lhSysMenu, MF_SEPARATOR, 0&, vbNullString) 
lRet = AppendMenu(lhSysMenu, MF_STRING, IDM_ABOUT, "歪歪的VB技巧") 
FormName.Show 
lProcOld = SetWindowLong(FormName.hWnd, GWL_WNDPROC, AddressOf SysMenuHandler) 

End Function 

　　第四步在form窗口的代码框中加入下面的代码 
Option Explicit 
Private Sub Form_Load() 
Dim d As String 
d = SubClass(Form1)  
'这里Form1要换成你窗口自己的名字 
End Sub 
Private Sub Form_Unload(Cancel As Integer) 
SetWindowLong Me.hWnd, GWL_WNDPROC, lProcOld 
End Sub