Konverter til html mail

Hej eksperter
Jeg har en mail sender

#### KODE ####
Dim sb As New StringBuilder()

        sb.Append("<html>")
        sb.Append("<body>")
        sb.Append("<table><tr><td>hello world!</td></tr></table")
        sb.Append("</body>")
        sb.Append("</html>")

        Dim mailMsg As New MailMessage("xxx@xxx.dk", "xxx@xxx.dk")
        With mailMsg
            .Subject = "xxxxxxxxxx"
            .Body = sb.ToString
        End With

        Try
            Dim client As New SmtpClient("smtp.mail.dk")
            client.Send(mailMsg)
            MsgBox("Your email has been successfully sent!", MsgBoxStyle.Information)
        Catch exp As Exception
            MsgBox("The following problem occurred when attempting to " & vbCrLf & exp.Message, MsgBoxStyle.Critical)
        End Try

#### KODE SLUT ####

Nu vil jeg gerne vide hvordan jeg kan konvetere det til html