It'll work yes but you'll need a new adapter and you might have to buy all of your games from America too. No news on if PS4 games will be region free yet. Technology wise from tv to socket everything will be compatible though.
For blu-ray films it will almost certainly not be region free so if you have a blu-ray collection now or intend to buy any they won't play on an imported console.
Most of the results on Google say that it will be region free. What adapter do you mean?
Just the power adapter. The PS3 is apparently region free although I've never tried imported games on mine but there's so few details on the PS4 right now if anyone says the PS4 will be region free then they're guessing.