If you have alot of things connected to your local net you will eventually want to give every gadget it's own, static IP. Here's a brief description on how to do that on your Raspberry Pi. I have a WIFI dongle attached to mine and I wanted both the LAN and WIFI to have the same IP (as I will only connect either the LAN cable or use the WIFI dongle)
In your terminal, type:
sudo nano /etc/network/interfaces
Now, copy in the following, replace XX with the IP you want on your Pi:
auto lo iface lo inet loopback allow-hotplug wlan0 iface wlan0 inet manual wpa-roam /etc/wpa_supplicant/wpa_supplicant.conf auto wlan0 iface wlan0 inet static address 192.168.1.XX gateway 192.168.1.1 netmask 255.255.255.0 network 192.168.1.0 broadcast 192.168.1.255 auto eth0 iface eth0 inet static address 192.168.1.XX gateway 192.168.1.1 dns-nameservers 8.8.8.8 8.8.4.4 netmask 255.255.255.0 network 192.168.1.0 broadcast 192.168.1.255
Press CTRL-O to save and then CTRL-X to quit the nano editor. You must also edit the /etc/wpa_supplicant/wpa_supplicant.conf file. Type:
sudo nano /etc/wpa_supplicant/wpa_supplicant.conf
Edit the settings to match your WIFI SSID and password
ctrl_interface=DIR=/var/run/wpa_supplicant GROUP=netdev update_config=1 network={ ssid="YOUSSIDHERE" key_mgmt=NONE auth_alg=OPEN wep_key0=YOURWEPKEY/PASSWORD HERE }
Press CTRL-O to save and then CTRL-X to quit the nano editor. Then reboot your Pi with:
sudo reboot