Located at Cheese Steak Central, 9th and Passyunk, across from Pat's Steaks.  Order your steaks at the first window.  Your drinks and fries at the next.  Read the sign next to the window.  It explains how to specify the cheese for your cheese steak.  But the only authentic cheese steak is one cheesed with Cheese Wiz.  When you get to the window all you need say is "Wiz, with."  They'll take it from there.  

I'm partial to a cheese steak hoagie "with."  That's a wiz cheese steak with fried onions, lettuce and tomato.