How to install wifi on Raspberry Pi is a handy, simple description of bringing up WiFi on a Raspberry Pi.
Following this guide, everything worked on the first try.
Note that prior efforts to bring the WiFi interface up from the command line were unsuccessful; the iw, ip, iwconfig, and ifup commands did not bring the wlan0 interface up.
The connection to the Pi in this instance was an SSH connection; the Pi running headless with X11 forwarded across and SSH tunnel via VNC, so the eth0 connection was active until disabled from wicd after wlan0 was successfully provisioned.
Note that the WiFi configuration for the dongle – wlan0 – does not appear to have been saved on reboot; Pi still comes up with Ethernet eth0 active, and the wlan0 module loaded and showing in the iwconfig ougtput, but the interface is not up, does not have an IP address, and no routing nor gateway configured for it.
