As the final four "American Idol" contestants -- David Archuleta, Jason Castro, David Cook and Syesha Mercado -- vie to be crowned season seven's champion, the quartet revealed its thoughts on their "

As the final four "American Idol" contestants -- David Archuleta, Jason
Castro, David Cook and Syesha Mercado -- vie to be crowned season seven's champion, the quartet revealed its thoughts on their "Idol" experience, musical pasts and future plans in a series of exclusive Billboard.com interviews.

As part of an extensive Q&A, Mercado tells Billboard's Fred Bronson that she started watching "Idol" the first year it was on, but then only "watched on and off because I was too busy ... doing school activities." It was Fantasia, season three's winner, who drew Mercado back in and inspired her to audition for the show.

As an "Idol contestant," Mercado says the most important lesson she's learned is "to relax, because sometimes I can be a perfectionist and I can rehearse so much."

Mercado also says that after "Idol," she wants "to work on an album." But the ambitious young singer has other dreams, too: "Star in a Broadway show. I [also] want to star in a movie."

In Archuleta's interview, he says he still feels "weird when people say,
'You're a good singer,' because I've never looked at myself like that. I've always looked at myself as someone who loves music and loves to try and interpret it as I see it."

His earliest musical memories are of his dad playing trumpet "all the time" and his mom "singing with her sisters." Now, he says, music is "all I think about. I don't have time to really concentrate on anything else."

For his part, Cook explains that he "grew up watching my father play
guitar." Cook also says his method for selecting songs to sing on
"American Idol" has involved "an idiot savant aspect": "If the vibe of a song grips me ... that's usually a good indicator that I probably should do that song. As far as arrangement, I operate on the mantra just keep it simple, stupid."

Castro tells Billboard that while his "whole family is musical, starting
with my grandfather on my dad's side," he "never sang.... I chose drums [because] I thought drums were cooler than everything and everybody played guitar."

He also says he knew from the start he'd do well on "Idol": "From the
beginning, I had this vision.... I thought what I did could maybe work and I thought people might like it. It's really cool when your ideas turn out to be true and so I did see this happening."

One of the four will be eliminated from the competition on Wednesday (May 7), but all four, along with the six previously voted-off contestants, will be performing on the "Idols Live" tour this summer. Visit Billboard.com next week for interviews with the other six "Idols Live" performers.

READ ALL FOUR EXTENSIVE Q&As WITH THE "AMERICAN IDOL" FINALISTS.