The google blog post about it
http://googleblog.blogspot.com/2012/...or-iphone.html
Google Maps is now available for iPhone
December 12, 2012
People around the world have been asking for Google Maps on iPhone. Starting today, we’re pleased to announce that Google Maps is here—rolling out across the world in the Apple App Store. It’s designed from the ground up to combine the comprehensiveness and accuracy of Google Maps with an interface that makes finding what you’re looking for faster and easier.
The app shows more map on screen and turns mobile mapping into one intuitive experience. It’s a sharper looking, vector-based map that loads quickly and provides smooth tilting and rotating of 2D and 3D views. The search box at the top is a good place to start—perhaps by entering the name of a new and interesting restaurant. An expandable info sheet at the bottom shows the address, opening hours, ratings and reviews, images, directions and other information.