Like others have said, you need an amplifier to drive the speakers so they are best used hooked to a home theater system or an inline amplifier hooked between the speakers and your TV. Amplifiers built into TVs typically have just enough power to drive the TV's speakers only. Check your TV owner's manual.
Yes you can. You will need to purchase speaker wire with bare wire at one end (for the speakers) and phono jacks at the other end that fit your t.v. audio out sockets. Radio Shack probably carries these.