Find-A-Control app (CAD/Software/Computers)
For the iPhone (or Android for that matter) you could do this for free, but it would take a little bit of time. Download the Esri ArcGIS for iOS App (free), establish an ArcGIS Online account (free), then download the shapefiles for the control in your area in shapefile format from the NGS website (free, I did this per county in my area). Once you have the shapefiles (ZIP format), import them into ArcGIS Online and then log into your account on the Esri ArcGIS for iOS App and your map will show up with any background data you define (digital orthos, roads, etc.).
I have been playing around with this for a while and works quite well, but you do have to spend a little time.
GPS and Survey Solutions Manager
The Sidwell Company