My cheap Japanese phone can tether -- but the carrier makes a distinction between packets originating from the phone and those from the computer, and they charge extra through the nose for PC packets (100$+ per month if you exceed a few megabytes, in extra to normal phone charges). All this while I can get a dual-mode WiMAX/3G WiFi router that fits in a pocket, has a day of battery life, unlimited data and transfers much faster for 50$/month. The problem isn't the hardware, it's the carriers.