It's just WiFi, so yes it will work.
Just to be clear however, this is nothing like having data service through a cell network. It relies on already existing WiFi hotspots...which means it would only work in very public areas like malls, or places like Starbucks and McDonalds. And those places usually have free, public and open WiFi networks to begin with.
This app isn't going to be of much use 90% of the time...like when you're on the move, or driving in the car, for instance.