I just pounced on this app on the mtn app store, it's eko city app (http://nexva.com/30941), though just for blackberry, the developer(s) did a very good job for us in Lagos. The app has a business directory feature, as well as GPS like navigation feature. Business owners could exploit the navigation feature to guide customers to their business doorstep from wherever they may be in Lagos. The app has lots of features, but am more excited about the business directory feature. I heard they have a version for Portharcourt. Finally Nigerian developers are coming up with reasonable content.