If you're working with a Raspberry Pi, you can attach a Wi-Fi dongle (like this one)
to get wireless access on the device.
To connect to a WPA authenticated wireless network:
$ wpa_cli > scan > scan_results > set_network 0 > set_network 0 ssid "<ssid>" > set_network 0 psk "<password>" > enable_network 0 > save_config # (Ctrl+C to exit)
Note: you need the double quotes.