This small script -- to be run as the superuser or someone with permissions to run iwlist -- will give you a list of the networks available.
iwlist wlan0 scan | grep 'ESSID' | sed 's/.*ESSID:"\(.*\)".*/\1/g'
Put it in a executable file in a bin directory.
Sometimes, you'll get the message
wlan0 Interface doesn't support scanning : Device or resource busy
And this normally goes away eventually, retrying the command.