Code:
Public Function GetBetween(ByRef sSearch As String, ByRef sStart As String, ByRef sStop As String, _
                                                    Optional ByRef lSearch As Long = 1) As String
    lSearch = InStr(lSearch, sSearch, sStart)
    If lSearch > 0 Then
        lSearch = lSearch + Len(sStart)
        Dim lTemp As Long
        lTemp = InStr(lSearch, sSearch, sStop)
        If lTemp > lSearch Then
            GetBetween = Mid$(sSearch, lSearch, lTemp - lSearch)
        End If
    End If
End Function

'Usage:Text1.Text =  Getbetween("123 get this 321","123","321")