One of the more frustrating aspects of Batman: Arkham Asylum, for me, was the lack of a minimap in the hud. I appreciated the clean view afforded by a minimalist HUD, but it made hunting up Riddler Trophies and clues, with the aid of a GameFAQ, of course, a chore marked by constant pausing.
An official map application for iOS devices, available now, should make the process more convenient in Arkham City. It's more or less a strategy guide for completionists, showing the location of more than 350 collectibles, broken down by character (Batman, Catwoman) and including locations of Riddler riddles. The app also allows the user to mark which ones he's found, so instead of stumbling across one on another mission and reminding yourself to come back to it, or going through the collectibles in order, is no longer the most painless way to finish the job.
The app is $3.99 and it is official. It has a few seconds of loading time in and out of each map, but they are zoomable.