I have used certain apps. Mainly parcel apps (for landowner names. Works similar to the onXmaps chips. onXmaps even has the app now for android and iPhone. Most of my apps are for maps. Nothing to do with calls or anything and mainly used in preseason. Otherwise my cumulative effort in the preseason winds up as waypoints on my GPS. Here is a link to a post I wrote last year about how I use apps and google earth (also an app on the phones but im not a fan of the phone version) to scout what I can at home before leaving to see it in person.

http://starvingoutdoorsman.wordpress...-google-earth/

That being said, I still take and use good ol maps and compass if I plan to go very far.