Codenstuff.com

Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
        For Each FontType In System.Drawing.FontFamily.Families
            ComboBox1.Items.Add(FontType.Name)
        Next
    End Sub

    Private Sub ComboBox1_SelectedIndexChanged(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles ComboBox1.SelectedIndexChanged
        RichTextBox1.Font = New Font(ComboBox1.SelectedItem.ToString, 10, FontStyle.Regular)
    End Sub

        Dim Fonts As New System.Drawing.Text.InstalledFontCollection()
        Dim Family As FontFamily
        For Each Family In Fonts.Families
            ComboBox1.Items.Add(Family.Name)
        Next

 Try
            Dim nFont As New Font(cbFonts.Text, cbSize.Text)
            RichTextBox1.SelectionFont = nFont
        Catch ex As Exception
            MessageBox.Show(ex.Message)
        End Try