The international press won't get their first look at the documentary Dixie Chicks: Shut Up and Sing until its gala premiere at the Toronto Film Festival tonight. But EW.com got an early look at the sure-to-be-controversial doc in Los Angeles and can attest that the film will continue to bring the (ex?) country trio more plaudits from progressives and further condemnation from conservatives. And if you think singer Natalie Maines had some harsh words for President Bush in public, wait till you hear what she had to say about him behind the scenes.In one memorable scene, Maines watches news footage of the president being interviewed about the furor that followed the singer's on-stage comment that she was ''ashamed the President of the United States is from Texas,'' which resulted in the group being dropped from most radio stations, as well as protests and plummeting sales. ''The Dixie Chicks are free to speak their mind,'' Bush told Tom Brokaw at the time, adding, ''They shouldn't have their feelings hurt just because some people don't want to buy their records when they speak out. You know, freedom is a two-way street.''