week 1 article - phone a friend over wi-fi

Technology of wi-fi has made the possibility to phone our friends over network connection. We just buy a phone which is similar with cell phone but it uses wi-fi techonology.Then we are ready to chit-chat with our friends as long as we are in the same wi-fi network. Wondering if we can implement it in our campus, we can call our friends in very low rate or even free of charge . It will be quite fun and save our money :)

For more details, can read through this interesting article :
http://www.technologyreview.com/InfoTech/wtr_16122,258,p1.html