If on a userform, use the ControlTipText. If on a worksheet:
Put an image control (or another control that you can make to appear
invisible) on the worksheet just slightly larger than the commandbutton. Put
the commandbutton centered on the image control. Put your message in a label
control and make the label control visible = false. Then utilize the
mousemove event of the image control to hide the label and the mousemove
control of the button to make it visible.
Private Sub CommandButton1_MouseMove(ByVal Button _
As Integer, ByVal Shift As Integer, _
ByVal X As Single, ByVal Y As Single)
Label1.Visible = True
End Sub
Private Sub Image1_MouseMove(ByVal Button _
As Integer, ByVal Shift As Integer, _
ByVal X As Single, ByVal Y As Single)
Label1.Visible = False
End Sub