With technology today, it is possible for musicians to write and record songs without ever setting foot in the same room. As long as each musician has compatible software and the file format is the same for each person, you can accomplish some pretty amazing music. The most common file for recording is a "Wav" file. They are large files but they also carry good quality sound. I've created music with a number of musicians, including ones outside of my own country of Canada and the results are very solid. You can meet musicians that like to do this on forums such as this one and then connect via email or Facebook to get the idea for the song across to all participants. One person will have to create the first part that everyone else is to follow for them to create their own part. You have to be able to play to a "click track" or what is commonly known as a "Metronome". You will find it very hard to make it anywhere in the music industry today without the ability to play to a click track. I've created a video explaining how I've done a few songs with a guitarist named Mike Cliffe. He and I have recorded 5 songs, one of which included a female singer/ keyboardist from Sweden. None of us had ever met when we did that particular song yet, we sound like a band that's been together a few years. Anyways, here's a video of how it's roughly done with a few samples from an upcoming release called "Snarg" by Mike Cliffe and I.