Nintendo promised online play for the retro games it'll make available via the Switch's online service, but if you'd rather not wait until this September for that, there's an unofficial way to play games of yore over the internet. It's through an emulator called SNES Party. "SNES Party is an experimental way to play SNES games with your friends online all from within your browser using WebRTC," the developers write. It works pretty well too.
If you're familiar with playing NES Party with friends, it's the same setup process. After creating a room, you're asked to load a ROM file and from there, WebRTC streams the video and controls to the other folks you're playing with. We tried it out with Bomberman and it went off without a hitch.
Of course, given Nintendo's litigious reputation don't expect this service to stick around for too long. Maybe it'll last until the company gives further details of how and when we'll get to start playing NES classics with our friends on the Switch. We can always hope.