Well, you'll need to obtain its hWnd (GetFocus, maybe?).  Once you have that, you
can translate mouse position to ListIndex something like this:

  Private Declare Function SendMessage Lib _
     "user32" Alias "SendMessageA" (ByVal hWnd As _
     Long, ByVal wMsg As Long, ByVal wParam As _
     Long, lParam As Any) As Long
  Private Const LB_GETITEMHEIGHT = &H1A1

  Private Sub List1_MouseMove(Button As Integer, _
     Shift As Integer, X As Single, Y As Single)
     Dim ItemHeight As Long
     Dim NewIndex As Long
     Static OldIndex As Long

     With List1
        ItemHeight = SendMessage(.hWnd, _
           LB_GETITEMHEIGHT, 0, ByVal 0&)
        ItemHeight = .Parent.ScaleY(ItemHeight, _
           vbPixels, vbTwips)
        NewIndex = .TopIndex + (Y \ ItemHeight)
        If NewIndex <> OldIndex Then
           If NewIndex < .ListCount Then
              .ToolTipText = .List(NewIndex)
           Else
              .ToolTipText = vbNullString
           End If
           OldIndex = NewIndex
        End If
     End With
  End Sub

Source:

  Ask the VB Pro, June 2000
  http://vb.mvps.org/articles/ap200006.asp

That was originally written for Classic VB, of course, but the same general
principles apply.  In this case, you're only after the value NewIndex.

No designated Rightclick event.
But however, you can mimick it, using the MouseUp (or Down) event
and catching the Button callback:
1 is the left- and 2 is the right mousebutton.

Private Sub ListBox1_MouseUp( _
   ByVal Button As Integer, _
   ByVal Shift As Integer, _
   ByVal X As Single, _
   ByVal Y As Single)

   If Button = 2 Then
       If Me.ListBox1.ListIndex > -1 Then
           MsgBox Me.ListBox1.ListIndex
       Else
           MsgBox "No Selection"
       End If
   End If
End Sub

Krgrds,
Perry

No designated Rightclick event.
But however, you can mimick it, using the MouseUp (or Down) event
and catching the Button callback:
1 is the left- and 2 is the right mousebutton.

Private Sub ListBox1_MouseUp( _
   ByVal Button As Integer, _
   ByVal Shift As Integer, _
   ByVal X As Single, _
   ByVal Y As Single)

   If Button = 2 Then
       If Me.ListBox1.ListIndex > -1 Then
           MsgBox Me.ListBox1.ListIndex
       Else
           MsgBox "No Selection"
       End If
   End If
End Sub

Krgrds,
Perry

No designated Rightclick event.
But however, you can mimick it, using the MouseUp (or Down) event
and catching the Button callback:
1 is the left- and 2 is the right mousebutton.

Private Sub ListBox1_MouseUp( _
   ByVal Button As Integer, _
   ByVal Shift As Integer, _
   ByVal X As Single, _
   ByVal Y As Single)

   If Button = 2 Then
       If Me.ListBox1.ListIndex > -1 Then
           MsgBox Me.ListBox1.ListIndex
       Else
           MsgBox "No Selection"
       End If
   End If
End Sub

Krgrds,
Perry