ASUS on Friday launched the P835 as its new, range-topping touchscreen smartphone and one of its first more conspicuous challengers to the iPhone. The phone depends on a 3.5-inch, 800x480 touchscreen but also adds a BlackBerry-like trackball for one-handed navigation and quicker scrolling. ASUS bases the phone on Windows Mobile 6.1 but tries to get around interface limitations by implementing a
