Here’s list of 5 iPhone GPS apps you could download to your iPhone. 
The apps below are easy to apply and are free or cheap.
They each offer something a little special,
and you could utilize them for various tasks.
Transform your iPhone into a mobile navigation device with a variety of useful functions. NAVIGON for iPhone is easy to use and provides information on route distance, time of arrival, motorway services, filling stations, speed limits and border crossings. What’s more, special destinations such as theatres, hotels, shopping centres and other sights are already integrated. Thanks to smart address input and realistic map display, you never lose track and always reach your intended destination safely. The pocket navigation system is a great companion – not only in the car – and is also ideal for optimum route planning and navigation for cyclists and pedestrians. The new route guide for your iPhone, the ideal companion for all frequent travelers.
It’s packed with powerful features designed to make your life simpler, easier and more convenient. Use voice commands to find a destination or service just by speaking the words. It makes driving safer and, honestly, it’s just very cool.
Telenav’s turn-by-turn driving directions are spoken by a real human voice. If you miss a turn, Telenav GPS Plus will automatically reroute you. Telenav’s cheap gas price finder is updated daily, so you always know how far you have to go to find the best gas prices in the area. Telenav GPS Plus lets you automatically post arrival check-ins and your favorite destinations on your Facebook® wall.
MotionX-GPS offers an all-new user experience to provide faster and easier access to the features users want, with full support for both portrait and landscape orientation and an elegant new menu design. This gives users the flexibility they need to conveniently mount their iPhone for quick and easy interaction, whether running with an armband or biking with a handlebar mount.
New features for iOS 5 include integration with Twitter to allow users to keep their friends and followers up to date on their latest outdoor adventures, and intuitive use of iOS 5 Notifications to complement voice coaching while the screen is turned off. In all, the update includes 18 new features and enhancements:
Google Maps Navigation is an internet-connected GPS navigation system with voice guidance. Speak your destination instead of typing (English only).An indicator glows green, yellow, or red based on the current traffic along your route. Touch it to see traffic ahead of you. Search for any kind of business along your route, or turn on popular layers such as gas stations, restaurants, or parking. View your route overlaid on 3D satellite views with Google’s high-resolution aerial imagery. Select the Navigation icon from the launcher to start quickly; pick a destination by search (speak or type), contacts, starred items, or recent destinations. Get voice-guided navigation for walking directions. Device vibrates for turn notifications. Get navigation for public transit directions in 400 cities around the globe. Device shows location along transit route and provides alerts for when to stay on or exit public transit.
GPS Essentials -The Swiss army knife of GPS navigation!
The most complete GPS tool on market: Navigate, manage waypoints, tracks, routes, and build your own dashboard from 45 widgets. Shows navigation values such as: Accuracy, Altitude, Speed, Battery, Bearing, Climb, Course, Date, Declination, Distance, ETA, Latitude, Longitude, Max Speed, Min Speed, Actual Speed, True Speed,Sunrise, Sunset, Moonset, Moonrise, Moon Phase, Target, Time, TTG, Turn. Show the orientation of the earth’s magnetic field, shows an arbitrary tracking angle and the current target. Also a marine orienteering compass, Record tracks and view them on map. Export KML files and import into Google Maps, Google Earth and others. Convert mail addresses of your contacts to waypoint so that they can be used within the app.