If your cell phone has the WiFi capability then all you need is the password for the wireless network that your trying to connect to.
You can go into settings on the phone and if you have that capability then you will have a place where it says to turn on or connect to a wireless network or WiFi.
On my phone which has ICS from Android when I press settings the first choice is wireless networks and it has WiFi , Blue Tooth and Mobile network. Each one has an on/off slider switch to turn it on and off. When connecting to my wireless network for the first time , when I set the switch to on it asked for the password to the wireless network.