ho cercato in giro e nella documentazione di VB.NET ho trovato questi codici:

Per il TcpListener e quindi lato server:

codice:
Imports System
Imports System.IO
Imports System.Net
Imports System.Net.Sockets
Imports System.Text
Imports Microsoft.VisualBasic


Class MyTcpListener

    Public Shared Sub Main()

	Dim server As TcpListener
	server=nothing
        Try
            ' Set the TcpListener on port 13000.
         Dim port As Int32 = 13000
         Dim localAddr As IPAddress = IPAddress.Parse("127.0.0.1")

         server = New TcpListener(localAddr, port)
         
         ' Start listening for client requests.
         server.Start()
         
         ' Buffer for reading data
            Dim bytes(1024) As Byte
            Dim data As String = Nothing
         
         ' Enter the listening loop.
         While True
            Console.Write("Waiting for a connection... ")
            
            ' Perform a blocking call to accept requests.
            ' You could also user server.AcceptSocket() here.
            Dim client As TcpClient = server.AcceptTcpClient()
            Console.WriteLine("Connected!")
            
            data = Nothing
            
            ' Get a stream object for reading and writing
            Dim stream As NetworkStream = client.GetStream()
            
            Dim i As Int32
            
            ' Loop to receive all the data sent by the client.
            i = stream.Read(bytes, 0, bytes.Length)
            While (i <> 0) 
               ' Translate data bytes to a ASCII string.
               data = System.Text.Encoding.ASCII.GetString(bytes, 0, i)
                    Console.WriteLine("Received: {0}", data)
               
               ' Process the data sent by the client.
               data = data.ToUpper()
                    Dim msg As Byte() = System.Text.Encoding.ASCII.GetBytes(data)
               
               ' Send back a response.
               stream.Write(msg, 0, msg.Length)
                    Console.WriteLine("Sent: {0}", data)
              
               i = stream.Read(bytes, 0, bytes.Length)

            End While
            
            ' Shutdown and end connection
            client.Close()
         End While
      Catch e As SocketException
         Console.WriteLine("SocketException: {0}", e)
      Finally
         server.Stop()
      End Try
      
      Console.WriteLine(ControlChars.Cr + "Hit enter to continue....")
      Console.Read()
   End Sub 'Main

End Class 'MyTcpListener
Per il TcpClient e quindi lato client:

codice:
 
Shared Sub Connect(server As [String], message As [String])
   Try
      ' Create a TcpClient.
      ' Note, for this client to work you need to have a TcpServer 
      ' connected to the same address as specified by the server, port
      ' combination.
      Dim port As Int32 = 13000
      Dim client As New TcpClient(server, port)
      
      ' Translate the passed message into ASCII and store it as a Byte array.
      Dim data As [Byte]() = System.Text.Encoding.ASCII.GetBytes(message)
      
      ' Get a client stream for reading and writing.
      '  Stream stream = client.GetStream();
      Dim stream As NetworkStream = client.GetStream()
      
      ' Send the message to the connected TcpServer. 
      stream.Write(data, 0, data.Length)
      
      Console.WriteLine("Sent: {0}", message)
      
      ' Receive the TcpServer.response.
      ' Buffer to store the response bytes.
      data = New [Byte](256) {}
      
      ' String to store the response ASCII representation.
      Dim responseData As [String] = [String].Empty
      
      ' Read the first batch of the TcpServer response bytes.
      Dim bytes As Int32 = stream.Read(data, 0, data.Length)
      responseData = System.Text.Encoding.ASCII.GetString(data, 0, bytes)
      Console.WriteLine("Received: {0}", responseData)
      
      ' Close everything.
      stream.Close()
      client.Close()
   Catch e As ArgumentNullException
      Console.WriteLine("ArgumentNullException: {0}", e)
   Catch e As SocketException
      Console.WriteLine("SocketException: {0}", e)
   End Try
   
   Console.WriteLine(ControlChars.Cr + " Press Enter to continue...")
   Console.Read()
End Sub 'Connect
ho provato a farli comunicare ma il server si pianta nel loop (While True)
ho provato a inseririe il while in un thread separato ma va in errore comunque..come posso risolvere??