Tribeca fest puts on a 'United' front.(Tribeca Film Festival, 'United 93')(Brief...

Universal Pictures' "United 93" has been tapped to open the Tribeca Film Festival on April 25.

Paul Greengrass-helmed pic follows the saga of the hijacked United Airlines flight that crashed outside of Shanksville, Penn., on Sept. 11, 2001.

Tribeca brass said Wednesday that family members who lost loved ones aboard the flight, as well as members of 9/11-related orgs, will be on hand for the pic's preem, along with the filmmakers.

The film re-creates the doomed flight's story in real time.

"The events of 9/11 had a massive effect on me,