Few places are more materialistic than Las Vegas, with its grandiose hotels and stacks of cash. But at last week's CTIA (Cellular Telecommunications and Internet Association) convention-which showcased several acres of upcoming cellphone and wireless technology-the focus was less on material goods than on what you can do with them. The exhibits boasted no gotta-get-it-now phone, but they did promise many ways to do more with the phone you already have. From file-sharing to postcard-making, the latest possibilities go far beyond mere talk.