We played one team last year that had a 70" hi-def TV, and would show film to players during offense/defense (they were a true two platoon team), theater style.
We shoot formations on an iPad in the press box. We have the ability to send them to a iPad on the sideline for the QBs to see, but we typically don't. But the OC will review them in the press box while we are on defense, claims they are very valuable to him making adjustments.
HUDL is working on a new app that will allow the film you are shooting during the game to be sent to your iPad or phone in real time, with replay features. It's in beta test now. If it comes out next season, expect to see a lot more iPads on the sidelines.