One of the most anticipated PDA phones of the year, the Palm Treo 650 is the hottest Palm OS smartphone on the market. Following on the heels of the very successful Treo  600, the Treo 650 adds several key improvements that address the needs of road warriors and improvements in technology since the release of the 600 over a year ago. Sprint was the first US carrier out the door with the 650, and GSM versions for Cingular, AT&T Wireless as well as an unlocked version for use with any GSM carrier were released early Feb. 2005.