When you have shelled out for a swanky mouse like the Logitech VX Nano, you want to make the most out of your investment, which means making its programmable buttons work. However, many Linux distributions recognize most mice as generic pointing devices, so none of the fancy extra buttons work right out of the box. The btnx utility can help you to turn your mouse into the versatile tool it is meant to be.
btnx comes in two parts: the btnx daemon that does the behind-the-scenes work of managing mouse button events, and the btnx-config tool, a graphical front end that helps you configure mouse button actions. btnx's Web site provides packages for Ubuntu and openSUSE, as well as source code archives for other distributions. As often happens, the packages are a step behind the source code distribution, so if you want to install the latest version of btnx, you have to go the usual ./configure; make; make install route.
To configure your mouse, launch the btnx-config tool.