Sprint this afternoon switched on its promised WiMAX-based 4G Internet service in Atlanta, Las Vegas and Portland. The wide-area wireless gives users peak download speeds of more than 10Mbps and real-world averages of between 3Mbps and 6Mbps. Subscriptions vary depending on whether the device is static and range from $25 per month for a fixed-in-place connection to $30 for mobile and $50 for both
