Dim normalFont As New Font("Microsoft Sans Serif", 12, _
          FontStyle.Regular, GraphicsUnit.Point)
        Dim smallFont As New Font("Microsoft Sans Serif", 8, FontStyle.Regular, _
        GraphicsUnit.Point)
 
        rtb.Font = normalFont
        rtb.Text = "H2O"
        rtb.Select(1, 1)
        rtb.SelectionFont = smallFont
        rtb.SelectionCharOffset = -2

Those people who think they know everything are a great annoyance to those of us who do - Isaac Asimov