This from MapQuest:
Today,MapQuest released the new MapQuest 4 Mobile for iPhone application. This free application represents a leap forward in how people interact with maps,directions and local search on their iPhones. MapQuest 4 Mobile for iPhone includes one-tap category search,easy options for creating and following routes (multi-point and full-screen landscape view) and integration with MapQuest.com. Businesses also benefit with an option for placing branded icons in the app.
More at the MapQuest blog.