I have studied about Microsoft Bing Map Navigation. There is iOS support and sdk available at http://www.microsoft.com/maps/developers/mobile.aspx
Can anyone guide me how to use this in my application? My requirement is to create an application having functionality like Google Navigator does, displaying direction using GPS.
You cannot create a turn-by-turn navigation product using the Bing Maps (or Google Maps) SDK. You can use it to generate directions but cannot present any sort of alert for upcoming turns. From the TOU at http://www.microsoft.com/maps/product/terms.html:
this project might be a good starting point for what you are looking for: https://github.com/route-me/route-me