Hi,
My brother bought me an Arduino Wifi Shield for christmas, the thing is that I don't know how to use it? In which kind of project?
I have an Arduino Uno! 
Thank you!
My brother bought me an Arduino Wifi Shield for christmas,
Nice brother.
the thing is that I don't know how to use it?
Is that a question or a statement? Do you have a WiFi network to connect to? Is there some reason that the Arduino would want to connect to that network?
In which kind of project?
Generally, one that involves networking, wirelessly. Surely, you can think of some reason to have the Arduino accessible on the network. If not, connect an LED to it, and learn how to turn the LED on and off from a web browser. The Arduino will act as a server (using the supplied/modified example).
When that works, make the web browser display the status of the light.
When that works, work on having multiple browsers be able to modify the status of the LED AND display the current status. This is harder than it might seem, since the Arduino can't push status information. The clients (the browsers) need to pull it. Learning how to make clients pull information, without overloading the network, is a good exercise.
Thank you PaulS, yeah nice brother ahah!
I'll try that, thank you, if found this, pretty interesting: openhomeautomation.net