I've seen apps that alert you when you've hit a certain milestone on your monthly data, but I haven't seen any that break down usage app-by-app, with the ability to select usage by time frame (e.g., see what process consumed the most data yesterday). Anything like this on the market? My sister keeps complaining about inexplicable data consumption on her 4S, and I want to know what's eating it. Also, are there any apps that make turning cellular data or wifi off/on, a one-button step? I noticed it takes like 4 extra steps to disable cell data, and it would be a pain to do that every time you put the phone to sleep.