Are you looking for A. glass cut to size or, B. having a piece of glass you already have cut to size for you?
If it's A. I have to believe there's a glass shop in either the Ledgewood / Roxbury area or Belvidere area if you can't find one in H-town proper.
If it's B. that may be a tough call. Even if you find a shop, they may not cut your glass and just about none will guarantee the result. The only place I know of that will cut glass you bring them is Mesko glass on Washington St. in East Stroudsburg.