So this is how rumors get started.
It's all over the internet that the Justice League of America movie has been renamed "American Heroes."
It all started when Ain't It Cool News reported that Christian Bale was talking about the film (and how its going to be different from Batman Begins), and instead of giving it the name we all know, he called it, "American Heroes."
Personally, I think this is the equivalent of somebody interviewing Dan Castanella about the Simpsons movie, and him calling it, "Matt Groening's big dream project," and people thinking that "Matt Groening's Big Dream Project" was the new title.
The other possibility is that American Heroes is an international title. Remember how, in Britain, they used to call G.I.Joe "Action Force?" Same thing, I think. In fact, I'll bet when the G.I.Joe movie does come out, they will call it Action Force in the UK.
So don't sweat it. Nobody's going to change the name. Justice League it was, and Justice League it will stay.