Help with Arduino YUN

Hi, I´m using Arduino Yun, I´ve configured the WIFI network using my home wifi and it worked perfectly. But, I´m trying to configurate the wifi network using the wifi network of my collage which you conect without pass but after you need to identify yourselve with an user and a pass to can start surf web.
So, when I tried to conect it. It doesn´t works. Because I`ve not identified yet to get internet.
How can I solved it?

There is no easy way. This kind of wifi is called "captive portal". It requires a user interacting with a web page. Since there is no user on the yun, there is no human interaction.
Your only chance is to mimic that interaction. You should use some browser plugin like livehttpheaders or firebug (firefox) and developers tools (chromium) to sniff what params get sent to the captive portal (user, password... what else?)
Then you can try mimicking your browser using curl on the yun. If you are lucky, you will end up with something as simple as

curl -d 'username=foo&password=mygoodpassword' http://somesite.com/login

Thank you so much for your idea.
How you use curl on arduino yun?

You can use the Process class provided by the Bridge library, here an example http://arduino.cc/en/Tutorial/Process