Bing Maps iOS SDK gives developers a set of Objective C classes to develop iPhone and iPad applications within Xcode, along with documentation and several sample projects to help them get started quickly. The iOS map control supports Bing's road, aerial and hybrid aerial map styles, and includes the ability to add pushpins to the maps and access the user's location via the GPS to locate the phone on the map.
Bing says they've "separated" Bing Maps Controls from the Bing Maps services to lighten the load. This means you can use Bing Maps iOS Control in conjunction with Bing Maps REST Service (Geocoding and Routing) to build a fully featured mobile map app. Additionally, you can hit Bing search services to pull local listing info."
[Source: Bing Maps Blog]