In order to make the Raspberry Pi use a Static IP Address with the wireless adapter use the following command to edit the interfaces file:
sudo nano /etc/network/interfaces
The settings below give a Static IP Address of 192.168.1.161, make sure you have connected the wireless adapter and got a connection to your router first.
auto lo
iface lo net loopback
allow-hotplug wlan0
iface wlan0 inet manual
wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf
iface default inet static
address 192.168.1.161
netmask 255.255.255.0
network 192.168.1.0
broadcast 192.168.1.255
gateway 192.169.1.254
Obviously these settings are for my network, make sure you use the appropriate settings for your network.