If you are developing on Windows and would like to connect an Android-powered device to test your applications, then you need to install the appropriate USB driver. This document provides links to the web sites for several original equipment manufacturers (OEMs), where you can download the appropriate USB driver for your device.
However, this list is not exhaustive for all available Android-powered devices.
If you’re developing on Mac OS X or Linux, then you probably don’t need to install a USB driver. Refer to Setting up a Device to start development with a device.