Quote Originally Posted by perito
Excelent!
So now, each time a new client connects to my server, its username will be added to the listbox lbClients
How to send a msg to a specific Client (the one which is selected in the list box?)

thanks
You retrieve the selected username by using the SelectedItem property of the listbox (it returns an Object so it needs to be converted to a string).
You use the GetClientByName function to get the ConnectedClient instance connected to the username. Once you have it, call its SendMessage method.