Google Maps App
The iPhone has a free Google Maps app with turn-by-turn navigation and continuous tracking. If you use Google's Chrome browser and have a Google id (gmail sign-in), you can let Google know everything about you and make things super easy on yourself at the same time!
Once you have Chrome installed on your computer, and the Chrome and Google Maps app installed on your iPhone, follow these simple steps:
Make sure you're "signed in" on your Chrome browser on your computer.
Open your Google Maps in a new tab
Open the Chrome app on your phone
In the upper left corner click on "New Tab". It should show you all the tabs you have open in Chrome on your actual computer
Click on the tab with your Google Map. Allow it to use your location (will be auto prompted)
When it opens click the button in the top left that says "Open in the Google Maps app"
All done. Now you have your map synced with the one in your browser, and awesome GPS navigation.
Although I think it's a little Big Brother-ish, syncing Chrome between devices is awesome. I have my work computer, home computer, and phone all synced so if I'm looking at something cool at work, I can pull it right up at home without needing to search again or email myself URLs. Hope that's helpful