MeineMail.From = New MailAddress("xy@meineadresse.de")

smtp.Credentials = New System.Net.NetworkCredential("versand@meineadresse.de", _
  "Passwort")

Public Shared Sub SendMail() 
    Dim MeineMail As New MailMessage 
    Try 
      With MeineMail 
        .From = New MailAddress("xy@meineadresse.de") 
        .To.Add("Info@meineadresse.de") 
        .Subject = "Testmail" 
        .Body = "Hallo" 
      End With 
 
      Dim smtp As New SmtpClient("smtp.1und1.de") 
      With smtp 
         .Port = 465 
         .EnableSsl = True 
         .Credentials = New System.Net.NetworkCredential("xy@meineadresse.de", _
           "Passwort") 
         .Send(MeineMail) 
      End With 
    Catch ex As Exception 
      MsgBox(ErrorToString) 
    End Try 
End Sub