awanish: This is a chat room application, not an instant messenger. It could be modified to be an instant messenger. You would have to modify the server to keep a map of QTcpSockets to usernames (QStrings), and then each client would have to send the username along with each message they want to send. The server could then route the messages appropriately. But seriously, this is just an example program, and if you want instant messaging, I strongly recommend something like Jabber.