I tried VZ Navigator, AT&T Navigator, and Sprint Navigation on BlackBerry Curve handsets. All three applications are very accurate, and guide you along your route with no hassle.

The functionality of a cell phone GPS application depends on the phone's capabilities; on an ordinary flip phone, the app might not have the same array of features that it does on a BlackBerry. Also remember that the GPS functions are largely reliant on your cell carrier's network, so you won't be able to use them if you're out of range of a cell tower.

Powered by , the VZ Navigator service boasts an easy-to-navigate interface; the screens are loaded with info, whether in 2D, 3D, or bird's-eye view. For instance, in my tests the display showed the total trip distance as well as a smaller inset showing the distance to the next turn.

Unfortunately, Verizon had more trouble than the other services I tested in quickly locating gas stations, rest areas, and restaurants; in some cases I had to try several times to get results. In addition, the Verizon service posted traffic alerts only on screen (in contrast to the AT&T and Sprint services, which announced slowdowns verbally).

Like other carrier-branded cell phone GPS services, VZ Navigator costs US$3 per day or $10 per month. Find more information on the site.