Testing as a driver, I'd first set the route manually, either from the side of the road or from home. If you're a BlackBerry addict, you won't find tapping in destinations difficult. I'm BlackBerry-challenged, though, and I struggled to key in text. (I imagine I'd have the same hassle using the tiny keyboard on any cell phone.) That's why I prefer adding addresses on the carrier's Web site and then syncing them to the BlackBerry, which you can do with all of the apps.

Even better, though, is AT&T and Sprint's feature that lets you call a toll-free number and speak an address. When you do that, the application pauses and another disembodied voice reads back the address to check accuracy. On the Sprint application, you still have to navigate to a different screen to get the GPS to route you to the location, so you'll need to pull over to the side of the road; the AT&T app, in contrast, immediately begins delivering voice turn-by-turn directions.

(A brief aside: Location sharing is a nice tool, available on AT&T and Sprint devices using any TeleNav app (regardless of carrier or branding) for GPS navigation. It lets you send a location search result that you've found to other users--either as a link to view a map and a text message, or, if your buddy is also using a TeleNav-powered device, by launching the application. You can also share your search results through TeleNav's Web site or right from the BlackBerry. Way cool.)

Once I set the route, each device kept me on track. As you'd expect, I got a warning from a disembodied female voice that I'd need to turn or exit the freeway; I'd hear the alert again as I got closer to the upcoming turn or ramp.

Pressing the space bar repeated the instructions; adjusting the volume using the controls on the side of the BlackBerry was easy too. The AT&T and Sprint applications also verbally alerted me of traffic ahead; the warnings told me how far off the slowdown would be. The Verizon service posted traffic alerts only on screen--not good if you're driving alone.