Can you hack into iPhone or iPad remotely?

I am afraid that someone will hack my ipad remotely? Is it possible? If so what would they need to know?

Added (1). How to tell if it's been hacked?

Added (2). Do they need the devise to jail break?

You can hack an iPod/iPad largely the same way you do with a normal computer.

It is not your device would have to be jail broken.