Palm Inc. is offering Garmin Mobile XT software as an option on its Treo and Centro smartphones. Priced at $249 and loaded on a microSD card, the Palm GPS Navigator provides drivers with maps of the United States, Canada and Puerto Rico; turn-by-turn, voice-prompted directions, and millions of points of interest, plus updated traffic, fuel prices, hotel prices and weather forecasts. Traffic information is also available from www.traffic.com.