It depends on what TV you are plugging it into. If you have an LCD TV then they usually have a VGA port and so do most laptops. So you would need a VGA Cable (Which is a standard monitor cable).
http://www.google.co....num=1&ved=0CEYQrQQwAA
However some new laptops have a HDMI port and if your TV has a HDMI port you can use that.
If you are using an old TV (CRT) then it gets a bit more complicated.
Depends on the connection on your laptop and TV. I use an HDMI cable to join it up and it's realy good. There is another connection but I can't remember the name of it.