Consumer Reports tests GPS to show you the right way to go.
Many new cell phones-including the Samsung Instinct and the iPhone-are GPS enabled. Most major carriers are offering this feature.
Consumer Reports tested cell-phone GPS navigation to see how it stacks up against portable GPS units.
"With cell phones, you usually need to subscribe to a service plan to get navigation information," said Consumer Reports' Jeff Bartlett.
That can cost about $3 a day or $10 a month.
Testing showed cell-phone GPS is comparable to that of portable GPS devices.
Many carriers offer traffic information, too, a feature people like.
Most cell-phone screens and controls are small compared to a portable device, but like portable units, many GPS-enabled cell phones give spoken turn-by-turn directions, so you don't need to look at the screen.
However, a couple of the most popular cell phones-the Google and the iPhone-don't offer spoken directions.
"If you're an occasional GPS user, using it for business purposes or on vacation, cell phone-based GPS can be a good alternative," said Bartlett.
You want to look for a phone with a large screen and an easy-to-use keyboard, like ones on the Samsung Instinct or the Glyde.
But paying for a monthly GPS subscription for your cell phone can cost as much as buying a dedicated GPS device.
If you're a heavy GPS user, Consumer Reports says you're better off getting a low-cost portable unit.
Consumer Reports says a good basic GPS unit is the Garmin Nuvi 200.
It's easy to use and costs about $150.