I've been in 10+ hotels in the last couple months and everyone, with the exception of one, had it. All you need to do is hit MENU on the TV remote, scroll thru the menu till you find something like GO MOBILE, and enter the key ode they give you on your iPhone. I think it's standard.

Side note... I was in Montreal with friends. We both had suites. While relaxing one night in their suite, I was able to grab their code and program my phone. Lets just say my wife and I had a BLAST messing with their TV all night. They had no clue and thought the room was haunted. It's a good gag.