ZackyH, with a multitrack recording program, you just build up a song track by track so to speak. Then in the end you bounce it all down to 2-tracks(stereo), which you then can convert to any filetype you want it to be. If you want it to be small, and easy to send over the internet, mp3 is most commonly used I guess. Which is only 1mb at 128kbps/44.1kHz I think, so not that big.