Most Debian derivatives support the Penguin 802.11N USB Wifi Adapter out of the box. For a number of reasons Debian 6 does not. One of these being a packaging issue. The current firmware that is required for the device is included in the non-free repository. A free version of the firmware will be in the main repository in upcoming releases.
To install the wifi tools and firmware:
1. Add a "non-free" component to /etc/apt/sources.list, for example:
# Debian Squeeze/6.0
deb http://ftp.us.debian.org/debian squeeze main contrib non-free
2. Update the list of available packages and install the firmware-atheros and wireless-tools packages:
# aptitude update
# aptitude install firmware-atheros wireless-tools
If not already performed, connect the device to your system.
3. As the driver may already be loaded, reinsert the module to access installed firmware:
# modprobe -r ar9170usb ; modprobe ar9170usb
4. Verify your device has an available interface:
# iwconfig
5. Raise the interface to activate the radio, for example:
# ifconfig wlan0 up
6. Select your access point / router using the network applet (GUI if installed) or use a network command to connect