Private Declare Function GetSystemMetrics Lib "user32" _
    (ByVal nIndex As Long) As Long

Private Sub AddRightAlignText(mControl As ListBox, strText As String)
  Dim m_CheckWidth As Long
    If mControl.Style = 1 Then
        m_CheckWidth = ((GetSystemMetrics(71) + 2) * 15)
    End If
        strText = Space((mControl.Width - TextWidth(strText) - 100 _
        - m_CheckWidth) / TextWidth(Space(1))) & strText
    mControl.AddItem strText
End Sub

Private Sub Form_Load()
    With List1
        .AddItem "Linksbündig"
        Call AddRightAlignText(List1, "Rechtsbündig")
        .AddItem "Und wieder links"
        Call AddRightAlignText(List1, "Rechtsbündig")
        .AddItem "Und nochmal rechts"
    End With
End Sub