Stolen iPhone help! (find my iphone app)?

My iphone was stolen and I'm trying to find it using the find my iphone app. ONLY, my iphone is off. I know that it can't be tracked down when its off, so I wanted to know if I'll be able to see it from the app in my ipad (which shares the same account my iphone has) once it's turned on. It says that i need Wi-Fi to send a message or to make the phone make a sound, but does it need Wi-Fi to be able to be tracked? I know that alternatively to the Wi-Fi, you can also use the data plan, but once my phone is turned back on, the person will have to insert the pin, and because they won't know the code, the phone won't be active. Do you have any suggestions as to what i can do? Will i still be able to track down the phone even without Wi-Fi or the data plan, that is, by only having it on?

Call the service to track it.

Did you set up Find My iPhone in icould on the device before?
If you did, go to https://www.icloud.com/...cloud.com/ in your web browser. When you log in, Find My iPhone will immediately begin trying to locate the device. But if the device has been restored back to factory settings, Find My iPhone will fail to work.
Free anti-theft program like "iLostFinder" may be helpful. It will take pics of the thief when she/he tries to open your device and then send the pics to your email.

Sorry about the lose.

Call police to help you.

Find my iPhone should work even if the thief doesn't know the PIN, but you're right, the phone will need to be online (i.e.turned on, and on the cell data network).

The easiest way to track the phone is to go to www.icloud.com and sign in with your Apple ID and use Find my iPhone from there.