Palm on Monday launched the latest version of its Treo smartphone, the 800w, on the Sprint network. Aimed at business users, the digital assistant and mobile phone offers access to e-mail, voice calls and other forms of messaging. The 800w has a larger screen size — 320 x 320 — than the previous Treo model, the 750. With dimension of 2.2 by 4.41 by 0.73 inches and a weight of 5 ounces, the 800w is thinner and lighter than earlier versions running Windows Mobile. It includes hard buttons for e-mail and calendar as well as a five-way navigation button and on/off ringer switch.