From what I've seen unpaid internships aren't nearly as common as they used to be, but are still concentrated in certain white-collar fields such as law and finance.
I don't think I saw a single unpaid internship when I was searching for my senior internship in college.
Oh man, when the hiring manager says “not at first” with that sing-song lilt, the adrenaline hit was immediate. 15 years later and this still gets to me.