TeleNav today announced the official launch of version 5.2 of their cell-phone based GPS navigation product, TeleNav. Back in December '06 I reviewed version 5, which was already impressive. Since that review, TeleNav has added traffic, pedestrian mode, and more.
$10 a month for TeleNav. $15 a month for internet access in order to use TeleNav. That's $25 dollars a month in a day and age when you can get a decent dedicated GPS for $200-300. If your phone needs a GPS receiver, that's another 100 bucks. Even the most flawed units are better than TeleNav.
Add to this the fact that TeleNav has the worst customer support in the universe (they make Magellan look like Garmin in comparison) and I'd say keep far away from this one.