Cell Phones in Cuba.
As for your last two questions: 1) presumably, Cuban recipients of these phones would need to activate the phone with a local carrier, just like we have to do here. 2) No, not a chance. Cuba is 90 miles from the nearest US land.
And are Cubans allowed to answer? It seems like a repressive government would get itchy if its citizens could talk freely to any outsider who happens to call.
As of April 15th, ordinary citizens are allowed to buy cell phones, as well as computers, DVD players, and a bunch of other formally restricted electronic stuff.