It looks like it would be an analogue resistive type of touch screen - there appear to be 4 connections and two of them lead to lines that go up each side. I guess the others lead to lines across the top.
They will handle 5V without trouble.
Here is a wikipedia article for a quick intro on how they work:
and this one gives more info:
It would be worth reading through the spec sheet of the chip nima mentioned to find out how they do it - then implement it in code in the Arduino (or just use the chip).
They seem to be reasonably priced in that auction. FWIW, I have purchased from that seller recently without problem
