Okay... now that I know of the existence of this thread, I'm going to teach you Sharders how a PROPER Philly cheesesteak is made! I have the right, as I am the only Sharder from the Philadelphia area that I know of...
Take a package of Steak-Umms (hard to find outside of the Eastern Seaboard... I had to hunt for almost a month to find these in West Texas... Finally found them at Wal-Mart in the frozen goods section), break them up into a frying pan, on medium heat. Allow to brown. Mix in cheese, preferably American cheese, though a sharp provolone or cheddar works nicely for variety. While meat is browning, toast a buttered sub roll (or a hoagie roll, or a hero roll, or whatever your local vernacular calls it) to a golden brown, then remove it. Fill with delicious meat and cheese mixture directly from pan.
If desired, sautéed mushrooms, onions, and sweet or hot peppers can be added to this recipe, but to me, it's called a CHEESE-steak, therefore it only requires meat and cheese.
If you can't find Steak-Umms, shaved sirloin works just as well! The thinner, the better.