Hello, Where Am I?

With easy-to-use systems, you can get driving directions from your cell

I was about halfway across the George Washington Bridge, traveling from New York to New Jersey, when I knew I had to dump my wife. No, not as my partner in life, just as the navigator on our long car trips. The truth is that Verizon's VZ Navigator, running on a Motorola (MOT ) cell phone, not only gave me faster, more accurate directions but also never needed to pull over for rest stops.

Car navigation systems, in-dash or windshield-mounted, have been around for years, but they're pricey, at $1,000 to more than $2,000, and inconvenient to install. Now, cell phones have become credible navigators, too, providing maps and turn-by-turn driving directions.

There are two approaches. The first, from the carriers, is to send all the navigation data to GPS-enabled phones over the cell network and charge a monthly fee for unlimited use. Besides VZ Navigator, options include the Garmin Mobile and TeleNav service, both from Sprint Nextel (S ). All cost about $10 a month. But you lose your directions if you lose your cell signal.

The other tack, from navigation companies, is to sell you the routing software and map data. You install it yourself on the phone, usually via the removable memory card, and there's no monthly fee. These include ALK Technologies' CoPilot LIVE, TomTom's Navigator 5, and Destinator SP. If your phone isn't equipped with a built-in GPS receiver, you'll need to add an external one; it's about $100 and often comes bundled with the software.

All the systems I tried gave me turn-by-turn directions, 2D and 3D maps, millions of points of interest, and could keep track of favorite routes or regular destinations. Because the small display on a mobile isn't good for viewing maps or text while driving, the systems also use voice prompts over the handset's speakerphone.

I used the VZ Navigator service, which gets its data from Networks in Motion, with a Motorola V325 mobile phone. It gave me street-by-street directions from my New York City apartment to my upstate weekend house. In fact, it suggested a route I don't normally take that proved to be faster. Like all GPS services, VZ Navigator will let you choose the shortest or simplest route or receive directions that avoid highways or tolls.

The best part of having navigation on your cell phone is that you can also search for the best routes if you're walking or biking and use it to find nearby restaurants or ATMs. If you make or receive calls mid-journey, the navigation is simply suspended and then resumed with updated directions once you have finished your conversation.

If you've been reluctant to buy an in-car navigation system, you should take a look at the phone-based version. Personally, I'm finding that $10 a month is way cheaper than couples therapy.

By James K. Willcox

    Before it's here, it's on the Bloomberg Terminal.