arduino ethernet shield noob lost

Hi all, i justo bought a new arsuino ethernet shiel but i have never use anything like this before, so im a bit lost in this case, so i just want to connect the arduino to internet, and look out if a led changes its state....

but for this, i need a server or the web page its inside the arduino???

Study the examples at File->Examples->Ethernet

A client asks questions. A server provides answers.

Since the Arduino knows whether the LED is on or off, the choice of client or server seems pretty clear.

thanks, but if i want to use something more complicated like some sensors and motors on a device and i want to get the readings froms this sensors, and also control the motors.... its a server or a client??

The Arduino knows the answers (the sensor values). It can answer questions that contain data, like GET /?color=green&speed=89 by setting the green motor to a speed of 89 (Yes, that's a dumb example).

Servers know the answers, so you want the Arduino to be a server.