Instructions
Turn off your console and position it within reach of your modem. If you need to reach a long distance, measure the distance between your modem and console and purchase a cable that will span that distance.
Plug one end of the Ethernet cable into the "LAN" port on your modem, and plug the opposite end into the "LAN" port on the back side of your PS3.
Turn on your console and scroll to the "Settings" menu on the Xross Media Bar. Use the directional pad keys to scroll through this list until you reach "Network Settings."
Select the "Internet Connection" option and hit "X," then highlight "Enable" and hit "X" again.
Select "Internet Connection Settings" to begin the setup process. When prompted, select the "Easy" setup method.
Choose to establish a "Wired" connection, and hit "X."
Read the information displayed on your television, which shows results of an Internet connection search. Hit "X" to confirm the connection and initialize a connection test.
Keep the Ethernet cable firmly connected to your modem and console to maintain your Internet connection at all times.