This is Objective-C analog for some part of Mapsforge library for Android, which you can find there: http://code.google.com/p/mapsforge/
MapsforgeReader allows iOS applications to read compact .map files with vector maps. There is an example, which should be working without any settings.
This example is a simple view controller with modified RouteMe mapView on it. It consists of sub projects, and these ones have been changed or made by me:
MapsforgeReader. It parses .map file into primitives. This is almost copy-paste from Android's sources, but in obj-c, converted by me with help of java2objc tool (http://code.google.com/p/java2objc/). Note: the way to improve parser is to use j2objc (https://code.google.com/p/j2objc/) instead.
OpenStreetPad. This is project from here https://github.com/beelsebob/OpenStreetPad with some changes. I took CoreGraphics renderer from that project.
RouteMe. I made some changes like asynchronous tile loading and changing data source and renderer to my ones.
Another sub projects like Proj4 or sqlite were not changed, but I added them to make example project run without additional job.
Note: the last changes of Mapsforge_iOS had beed done in summer 2012, and some things can be changed.
Feel free to contact me with any questions: firstname.lastname@example.org.