How would one go about burning demos to a disc in OSX? Will a regular old burning program work, and if so, are there any additional steps?
I'm not at all familiar with OSX but the basics of why the 360 demos working on burned discs (this is assuming that is what you are trying to do, from lack of specification). Any program that can burn folders to a disc will work. If you have a program that can burn the 'Content' folder and everything inside of that folder to a disc, then you can use that program to burn 360 demos.
As Dark Scyth mentions you can just burn the Content folder to a DVD like you would do on Windows, any burning program should be able to do that fine. Here is a quick guide I created on how to burn 360 demos on OSX without any additional applications: https://digiex.net/computing-sectio...-burn-xbox-360-demos-dvd-apples-mac-os-x.html