The www.linux-wlan.org site provides driver software and Linux compatibility information for a number of USB and PC Card wireless network devices.

One of the best places to start searching for drivers for a particular USB device is the Linux Wireless LAN HowTo document. While some of the information may be a bit dated, you can find information on Linux wireless drivers ranging from pre-802.11 standards up through more recent 802.11g and 802.11a devices.

If you still cannot find an open source hardware driver for your USB wireless network device you might look at the DriverLoader offering. DriverLoader delivers a compatibility-wrapper designed to enable the use of standard Windows NDIS drivers on Linux systems.

A free 30-day DriverLoader trial is available for download and the permanent license price is low enough to be quite attractive if DriverLoader works with your current USB device. Installation is straightforward, but you do need a copy of the Windows drivers for your device. To use Wi-Fi Protected Access security with DriverLoader, you need to download and install a second package named wpa_supplicant from the Linuxant download site.

Ndiswrapper
Finally, Ndiswrapper lets Linux users employ the Windows drivers provided by the device manufacturer with a Linux system. The package is available in source code and as a Debian package that can be installed using apt-get.

The software implements a Windows kernel API and NDIS API inside the Linux kernel, so the device runs natively, as it would in a Windows system.

This native Windows API implementation allows ndiswrapper to support a number of devices in addition to the wireless network devices for which it was designed. A list of devices known to work with the ndiswrapper driver is available.

To install from the source code, you need the Linux kernel source code that matches your system and the wireless-tools package. RedHat, Mandrake and Debian provide wireless-tools packages you can install with their respective package-management tools.

How to install ndiswrapper is well documented. Pay particular attention to the section on installing the appropriate Windows driver for your device. Once ndiswrapper is built and the Windows driver is installed, follow the instructions in the configuration section of the wiki to load the kernel module and configure the network interface.