Google has launched a 4G variant of its Nexus S smartphone on Sprint’s network, the company announced Monday in a blog post. The Nexus S features a 4-inch touchscreen display, 1 GHz Hummingbird CPU, 16 GB of storage memory, two cameras and near-field communication capabilities. Of course, its most interesting feature is its WiMAX chip, which enables fast data transfer on the move (theoretically, up to 40 Mbit/s ). The device will be available this spring online and in Sprint retail stores, as well as Best Buy and Best Buy Mobile stores in the U.S. for $199.99. Google also announced it has partnered with Sprint to enable seamless integration of Google Voice with users’ mobile phones. That means customers will be able to use their existing Sprint number as their Google Voice number, as well as replace their Sprint number with their Google Voice number when calling or texting from their Sprint phone. Furthermore, international calls made from Google Voice-enabled Sprint...