[taximania]

This was not done by me.
I think it's agraham who wrote this code.
I think the number 2 is correct for your needs.

Sub TextBox1_KeyPress (key)
    If StrLength( textbox1.Text) >=2 Then	
        If Asc(key)>31 Then
            ss = Textbox1.SelectionStart
            Textbox1.Text= SubString(Textbox1.Text,0,2)
            Textbox1.SelectionStart = ss
        End If
    End If
End Sub