Application like a p2p system

i want something to work like that. Here is what happened when you decided to look for the song: You opened the Napster utility. Napster checked for an Internet connection. If it found a connection, Napster logged you onto the central server. The main purpose of this central server was to keep an index of all the Napster users currently online and connect them to each other. It did not contain any of the MP3 files. You typed in the title or artist of the song you were looking for. The Napster utility on your computer queried the index server for other Napster computers online that had the song you requested. Whenever a match was found, the Napster server informed your computer where to find the requested file. When the server replied, Napster built a list of these systems in the results window. You clicked on the file(s) that interested you and then chose Download. Your copy of Napster attempted to establish a connection with the system hosting the file you selected. If a connection was successfully made, the file began downloading. Once the file was downloaded, the host computer broke the connection with your system. You opened up your MP3 player software and listened to the song.