dejo una versión simple y muy básica...
Option Explicit
Option Private Module
'//By JuanC - 6 de Septiembre de 2007
Private iLen As Integer
Private iCount As Integer
Private bStop As Boolean
Private sCadIni As String
Sub Iniciar()
[A1] = "By JuanC 2007"
sCadIni = [A1]
iLen = Len([A1])
iCount = iLen
bStop = False
Call Play
End Sub
Sub Detener()
bStop = True
End Sub
Private Sub Play()
Application.OnTime Now + TimeValue("00:00:01"), "runn"
End Sub
Sub runn()
With [A1]
If .Value = " " & sCadIni Then
.Value = sCadIni
iCount = iLen
ElseIf iCount = iLen Then
iCount = 0
.Value = Mid(.Value, 2) & " " & Mid(.Value, 1, 1)
Else
iCount = iCount + 1
.Value = Mid(.Value, 2) & Mid(.Value, 1, 1)
End If
End With
If Not bStop Then Call Play
End Sub
Saludos desde Baires, JuanC