Which movies in particular are you talking about?

Here it depends on the kind of movie -- super big budget movies like Dark Knight will come out at the same time or within a week or two of the US. Lower budget movies will take a bit of time say a few months, movies that the Yanks want to market as a "summer" movie will often be pushed to coincide with Argentine summer, and movies that are considered shoe-ins for Oscars won't come out until after they've won the Oscar! On the other hand, movies that the studios feel unsure about will actually come out here BEFORE they've screened in the US -- ie Up! was released in Argentina a few weeks before it hit screens in the US and a few months before it ever screened in the UK. We went and saw that crapola movie with Bruce Willis the other week -- the Substitues or whatever it's called in english. It hadn't yet been released in the States. I think it will end up a straight to DVD there! There's been a few other instances of that over the years -- we saw the movie Taken when it was in theatres here, it didn't come out in North America until about 6 months later.

If you want to know release dates for movies: http://www.imdb.com/Recent/Argentina

You can see from the list it's not that bad -- movies that came out July / August / September are coming out Oct / Nov here. All the movies that open on the 25th Dec in the US are opening Jan 1st here. The funniest one on that list is that Halloween II is opening in January -- a case of "wha?"...