Does find my Iphone need Wi-Fi?

Will it need a Wi-Fi/3G connection for to be able to use it? Do I need my GPS and data roaming on?
Iphone 4s

No that is a security feature built into your iPhone that is activated over a cellular network. It is used to wipe or lock your phone if it is lost or stolen.

Find My iPhone needs GPS if you want to see where it is, and some form of Internet connection (3G, 4G or Wi-Fi). If you turn on data roaming, all that will happen is that your phone will connect to 3G/4G when your abroad but this costs money on top of your monthly contract on an amount downloaded basis.

GPS is only for you own viewing pleasure…

Your Network Provider can trace you by Service… Or Cell Tower and get your exact location…

The security feature is built into the iphone…

Just like the auto-back up that takes place… And takes your pictures and videos and places them on a CLoud Service to get hack… When you never even uploaded the pictures online.

Sorry? You meant you want to connect your iPhone to Wi-Fi? If so, you just need to enable the Wi-Fi feature like this, http://www.mywifirouter.me/blog/searching-wifi-hotspot-for-iphone5-just-with-five-steps/. Then it can search for nearby hotspot automatically.