Sure, use the PopupMenu function. Here is an example from MSDN.
Code:
PopupMenu Method Example
This example displays a pop-up menu at the cursor location when the user clicks the right mouse button over a form. To try this example, create a form that includes a Menu control named mnuFile (mnuFile must have at least one submenu). Copy the code into the Declarations section of the form, and press F5.
Private Sub Form_MouseDown (Button As Integer, Shift As Integer, X As Single, Y As Single)
If Button = 2 Then
PopupMenu mnuFile
End If
End Sub
BTW, I don't know why but MS Help is often poorly written as in the example where the "magic number" 2 is used rather than the built-in constants for the mouse buttons which are:
vbLeftButton 1 Left mouse button
vbRightButton 2 Right mouse button
vbMiddleButton 4 Middle mouse button