[CaliforniaKarl]

It does, and it's called VATSIM[0]. VATSIM Radar[3] will show you what's going on right now.

As a pilot, you connect using either Microsoft Flight Simulator or X-Plane. Your flight simulator will include graphics (hopefully up-to-date) for your chosen area. Pick a starting airport, spawn at a ramp location (a gate, cargo area, etc.), connect to the network, file a flight plan (or go VFR), call up (or announce intentions), and go.

As a controller, VATSIM organizes ATC by region of the world, then in to 6-8 divisions within the region, then in to individual ARTCCs, ACCs, or FIRs[2]. You'll typically register with a division, then make your home in a particular ARTCC/FIR. For example, I was registered with VATUSA and made my home in the Indianapolis ARTCC.

There is software[1] for both pilots (connecting your flight sim to the network) and controllers (providing a radar display). Each "radio frequency" has an associated text chat and voice chat for communication. ATC are trained to support both text and voice simultaneously, following pilot's preference.

For controllers, your chosen ARTCC/ACC/FIR handles your training. They provide the "sectorfiles" that give you a graphical view of your airspace and your airports. (Think of it like a modern version of an old-style vector display.) They also help you through training, both book learning and sim training. You start controlling things on the ground, and work your way up to controlling things in the air.

[0]: https://vatsim.net/

[1]: https://vatsim.net/docs/policy/approved-software

[2]: Air Route Traffic Information Center / Area Control Center / Flight Information Region. Different countries use different terms, but mean the same thing: It's a large three-dimensional volume of airspace.

[3]: https://vatsim-radar.com/

[seabass-labrax]

Another useful tip: don't immediately register with the division local to you in the 'real world', but instead take a look at a variety to see how different divisions conduct themselves. Some divisions have very long waiting lists, and standards of service do differ between ARTCCs/FIRs. It's also worth just checking to see whether the software a given division uses is actually compatible with your computer, because they don't all use the same programs.

I've spent many hours in VATSIM and loved it, so don't be discouraged from diving in, but as a warning: I encountered a pervasive issue with pretentiousness across the VATSIM community, with some divisions setting largely arbitrary rules and procedures which don't exist in real world ATC.