How do you connect to a "computer to computer" wireless network?

I have noticed that whenever I search for wireless signals with my netbook, I get 2 or 3 wireless signals that say "Computer to Computer" wireless networks. It even lets you connect to it. But the internet still doesn't work. How, exactly, do these types of wireless signals work? The ones I always see are "Secretaria SEJ", "neolanusers", and "TEC"....at least at the place I work at there are those signals. So, how do I actually get internet from these signals?