With the advent of yet another Palm Treo device, it's not hard to believe analysts when they predict that one quarter of all wireless handsets will be either PDA or smartphone devices in just five years. The Treo 680, which will be available through Cingular, is a quad-band phone with a very inexpensive price tag--just under $200. In addition to supporting Good Mobile Messaging, users are provided access to the $10 per month TeleNav GPS Navigator service that offers turn-by-turn voice and on-screen driving directions. The software package also includes other directional aids for the mobile warrior such as full-color maps and the latest prices on fuel. Article