Rand McNally's new turn-by-turn navigation service for cell phones, called Mona, adds an interesting ease-of-use capability to the category: In addition to being able to punch in addresses on your cell phone with one hand (while your other hand is on the wheel), with Mona, you can also create a Web-based list of destinations in advance, which are downloaded to the phone for ready access.

All the cellular navigation services provide turn-by-turn directions on the cell phone display, voice prompts, and the ability to route you back on course if (that is, when) you get lost. The others are TeleNav's GPS Navigator, Verizon's VZ Navigator (based on Atlasbook from Networks in Motion), and the Motorola ViaMoto service, which continues.

Mona could be the easiest service to use for those who plan ahead. As with the others services, you can enter a destination from the cell phone's keypad, either an address or a point of interest (such as airport, ATM, or hotel).

But Mona also has a Web-based address book. Enter common addresses for local trips, then log in just before your vacation with likely stops, and they're all synchronized with your cell phone; at the same time, any destinations you entered on the phone are replicated with the phone's resident address book.

And for those of us who have technology-challenged in-laws, spouses, children, and so forth, someone else can log on to the Mona address book and add a destination; it's immediately replicated to the phone as the grandparents point their Town Car in the direction of Fort Lauderdale. With this feature, Mona offers much of the ease of use of the latest OnStar Turn-By-Turn Navigation service but without the necessity of buying a 2007 General Motors car. OnStar uses a live operator, but Mona's third-party lookup is more informal: a friend or relative.

Mona is the third wireless technology offering from Rand McNally, which is the leader in paper maps since the 1850s but has a more mixed record of timeliness on the digital technology front (in early June, its home page offered help to "find the perfect hotel for your Spring Break"). StreetFinder Wireless provides local maps for Sprint/Nextel cell phones, along with directions and points of interest, but it doesn't offer real-time turn-by-turn routing; and Rand McNally Traffic provides real-time traffic information (accidents and congestion) on most major carriers.

To read our article, "Cell Phones Learn to Navigate," click here.

To read our article, "Cell Phone Nav: The Next Big Thing," click here.

To read our review of the TeleNav GPS Navigator 4.0, click here.