The SNES9x emulator is a great way for older gamers to relive the wonderful Super Nintendo games of their childhood without having to pay hundreds of dollars on eBay for systems that are now fairly hard to find. The SNES9x emulator is doubly great in the sense that it is one of the few Super Nintendo emulators with the capacity to play these games with your friends online. This is accomplished through the SNES9x's Netplay function.
Open the SNES9x emulator.
Click on the "Netplay" drop-down menu at the top of the screen.
If you want to host the game session, click "Act As Server." If you are the server, you should let the person that you are playing with know your IP address so that he can connect to your computer.
If someone else is hosting the session, click "Connect To Server...". This will bring up a small window where you can enter the IP address of the host. There will also be another box where you can enter a port number, but the default port number that is already there should work for you.
After you are connected, you or the person you are playing with can start an old-school game of your choosing.
As online emulator play goes, SNES9X's Netplay is notorious for being one of the worst possible methods, because in spite of its name, it is primarily used for local network play. If one of the people playing has even a little bit of lag, it can ruin the entire session. Most emulator fans recommend using the ZSNES emulator or the Kaillera client, but the SNES9X Netplay option is still serviceable if you have no other options.