Google maps for iPhone is now available for free. You may need to have Google account like G-Mail for some features. Depending upon how much information you want Google to have about your location and travels, you may want to decline the offer to have Google store information about your travels, etc.
The developer describes the app as follows:
Navigate your world with Google Maps, now available for iPhone. Get comprehensive, accurate and easy-to-use maps with built-in Google local search, voice guided turn-by-turn navigation, public transit directions, Street View and more. Use Google Maps to discover great places to eat, drink, shop and play, with ratings and reviews from people you trust. Sign in to save your favorite places and quickly access all your past searches and directions from your computer, right on your phone.
* Find addresses, places and businesses around the world with Google local search.
* Discover places to eat, drink, shop and play, with ratings and local reviews.
* Sign in to sync your searches, directions, and favorite places between your computer and your phone.
* Get voice guided, turn-by-turn driving directions.
* Find your way by train, bus, subway or walking directions.
* Access live traffic information in cities across the world.
Street View and imagery
* View 360-degree panoramas of places around the globe with Street View.
* See inside more than 100,000 businesses worldwide.
* View high resolution satellite imagery of locations around the world.
Simple and easy to use
* An entirely new Google Maps experience on your iPhone.
* Newly designed and streamlined interface for even easier navigation of your world.
* Use gestures to explore the map and browse results.
Get the new Google Maps and say hello to Google search, voice guided navigation, transit directions, Street View, and much more.
Support for the app can be found here. The app is compatible with iPhone 3GS, iPhone 4, iPhone 4S, iPhone 5 and other iOS devices running iOS 5.1 or later. Although not made specifically for the iPad, it is an app worth trying on your iPad in 2x mode.