Well fscommand() is the way for the flash player to communicate with other programes, in this case the browser. You can use it to do preset things, like show or hide the rightclick menu, but you can also use it to run javascript functions in the html page. There's a very good tutorial on this in the tutorial section...get cracking!
When you've got the hang of communicating between flash and javascript, the script you need to run will be something like:
//Javascript
if (window.print) {
window.print();
}