I was thinking about getting one, but i dont really know what is it for. Like, how to connection it crap. Do you need a laptop or computer for it?

it replaces your Ethernet (blue) cable that bring internet to your xbox

you DO NOT need a laptop but a computer is required and a wireless rotor is also required

its not to hard to set up if your have a working wireless network in your house

plug it to the back of your xbox. turn it on (with no game in)
so it goes to the dash bored some where there should be prompts to connect to xbox live click it follow the stuff
eventually you will search for your network it will find it (hopefully) it may ask for a password that who ever set up you rotor should know
(Some networks are not locked)

If you have a wireless router this will let you connect the 360 to the internet wirelessly.

you need a computer and a wireless wifi thing GET IT HERE for free just signup get points and go to the xbox prize section and get the xbox wifi adapter WWW.TINYURL.COM/EVAN08

to tell you the truth it might be difficult for you. do you have wireless internet if yes then just buy a wireless xbox 360 adapter from walmart pr something for 85$