Wi-Fi for Raspbian

Check if Raspbian can see the USB device.

lsusb

the result should be something like

Bus 001 Device 002: ID 0424:9512 Standard Microsystems Corp.
Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
Bus 001 Device 003: ID 0424:ec00 Standard Microsystems Corp.
Bus 001 Device 004: ID 0bda:8176 Realtek Semiconductor Corp. RTL8188CUS 802.11n WLAN Adapter
Bus 001 Device 005: ID 05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB
Bus 001 Device 006: ID 05e3:0608 Genesys Logic, Inc. USB-2.0 4-Port HUB
Bus 001 Device 007: ID 4971:1020 SimpleTech

You can see my Wi-Fi device as device number 004.

Run the following commands

wpa_cli

from within this cli use the following commands

To view the current SSID's within range

scan

wait about 15 seconds for the scan to complete

scan results

Configure the required SSID

add network
set_network 0 ssid "ssid-name"
set_network 0 psk "psk-password"
enable_network 0
save_config
quit

Check for configuration

iwconfig

By default the interface will use DHCP to get an IP address. If you wish to assign a static IP address to wlan0 refer to Static_IP_Address_for_Raspbian

Here is a reference for my configuration
/etc/wpa_supplicant/wpa_supplicant.conf

ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev
update_config=1

network={
        ssid="ssid-name"
        psk="psk-password"
}