LOS ANGELES -- It's two hours before dawn, and Eduardo Sotelo, the star of America's top-rated morning radio show, greets the massive workforce that feeds and builds and spruces up the nation's second-largest city. "¡Despiertese!" he shouts. Wake up!

Maids get out of bed and slip on their uniforms, landscapers load leaf blowers into rusty flatbed trucks before chugging up the freeway and cooks turn on restaurant stoves to make flapjacks. They, like other listeners, know Sotelo as El Piolin, or Tweety Bird, and they regard him as a Mexican immigrant hero, someone like them, a role model. Twenty years ago, Sotelo sneaked across the Mexican border into California by hiding in the trunk of a car, and now his Spanish-language radio show, "El Piolin por la Mañana," has made him a rags-to-riches story, a DJ who beats Howard Stern, Rush Limbaugh and Tom Joyner every weekday morning, according to Arbitron ratings.

Tweety Bird in the Morning is probably the biggest radio show that most Americans have never heard of, and its quiet triumph over English language shows speaks volumes about the living arrangement between Americans and the estimated 11 million to 12 million immigrants who reside in this country illegally. These immigrants are hidden in plain sight, even as their numbers and purchasing power grow ubiquitously day by day.

Advertisers, however, have recognized their value -- "Forty million people, spending $700 billion -- it will be $1 trillion by 2010," says Moses Frenck, managing editor of Adweek's Marketing y Medios, which follows the Spanish-language industry, and "if you advertise on Piolin's radio show, you will have a whole cross section of people buying your product."

Sotelo downplays the attention, saying, "I just felt like another person that's putting a brick on the dream for 11 million people, living without papers. I went through it. I know the feeling, and you feel terrible. I don't want no one to go through that. It's painful."

Last month, Piolin pushed more than product on his show. He is credited for supersizing the city's March 25 immigration rallies to more than a half million, making America sit up and take notice of immigrant demands for reforms that would give them a chance to become citizens.

As a result, Sotelo's name crossed over to English-language media for the first time. He was the cover boy of LA Weekly's March 25-31 issue, in a staged photo, appearing frantic as he peeked out of a half-open car trunk. "Despiertese, Despiertese!" read the headline. "Piolin breaks out."

Sotelo's publicist, Georgia Carrera, says he's just been invited to the White House for its Cinco de Mayo celebrations.

"He's the biggest," says one fan, the Puerto Rican singer Noelia Lorenzo. "Whatever he says is like the word of God."

When alarm clocks go off at 4 a.m., Sotelo's high-pitched wake-up is the first word of the day for many of his listeners. It is followed by that crazy Looney Tunes music, mixed with a Mexican flair, playing off the Tweety Bird nickname. He broadcasts for seven hours, Monday through Friday, on KSCA (101.9 FM).

His show is heard in 17 markets and features your typical morning radio fare, entirely in Spanish. Aided by a five-man crew, Sotelo cold-calls area businesses, disguising his voice, asking for what can only be described as dumb stuff, until they're let in on the gag or hang up in frustration. He tells bromas -- jokes -- to canned laughter and devotes chunks of time to callers who dish their own. Here and there he plays wildly popular Mexican ranchero music, with its oompah-like sound.

Music, fun and games are a kind of medicine for listeners with difficult lives. His audience is full of people who risked life and limb to enter a foreign country illegally, and now find themselves alone, penniless, jobless and a step away from deportation. Grown men weep because they miss their mothers. Children wail because they can't find their parents.

And then there are people like Maria from Guatemala, who come to the studio to tell their stories to Sotelo and his listeners. Her 14-year-old daughter was raped by two guides in the city of Oaxaca in Mexico during their trip to the States, she says. The girl, Rosa, sits beside her, eyes down, hands on her swollen, pregnant belly.

Sotelo, like his audience, is riveted.

But the singer Lorenzo, who is also in the studio and agreed to donate money, notices something: Rosa's stomach. Didn't the mother say the baby was about due?

"The belly is bigger at that stage," Lorenzo whispers.

Sotelo stares into the mother's crying eyes. Part of his charm is his big heart, and sometimes people take advantage. He opens the phones to 500,000 upset listeners.

"Mentirosa!" cries the first caller. Liar! Caller after caller says the same. Lorenzo voices her doubts about the timeline. Finally, Sotelo weighs in. "Es un gran contradicion, mami," he says to the mother. That's a big contradiction. "¿No hay novio, esposo?" Is there no boyfriend, husband?

The show's over, and one by one, Sotelo, Lorenzo and the crew push past the disgraced mother to hug Rosa.

"This happens a lot," Sotelo says. "And it's sad, because so many people really need help. I want to help them."

* * *

In 1986, when he arrived in the United States from his home of Ocotlan, in Jalisco, Mexico, at age 16, Sotelo crossed over from Tijuana and clawed through the desert. He was almost captured by the Border Patrol when a helicopter hovered over him with a searchlight.

"I prayed to God to make me invisible," says Sotelo. The helicopter flew away.

Sotelo ran and jumped in the trunk of a waiting car. "At one point I couldn't breathe, so I lifted up the carpet and breathed through that tire hole," he says. "There were so many fumes. I thought I was going to die there."

He made his way to Santa Ana, attended Saddleback High School, where he was suspended several times for cutting up in class. He settled down, played varsity soccer, took theater classes, got a part-time job at a photo lab where his father worked, and graduated.

But there were few jobs available for a high school graduate with no green card. Sotelo picked up aluminum cans for recycling and washed cars. He listened to radio day and night, wondered what it would be like to become a DJ, and started practicing his radio persona by taping his voice on a clunky black cassette recorder.

He went from station to station, trying to get his break. Finally, he got a call from one in Corona, Calif., far out in the desert, in the Inland Empire. Sotelo could barely afford gas to drive there.

"Have you done news before?" the station manager asked. "Yes," answered Sotelo, who came in the next day and flopped. He says they let him stay because he worked for free, sleeping in his car, washing his face at a nearby park. Then one day he was fired for not having proper documentation.

Sotelo made his way to Sacramento, where the legend of Piolin truly began.

"We went to number one. Nobody thought we would ever do that," he says. "We were so young." He slept in an apartment with no furniture, and had gas money for the first time. But a competitor told immigration officials to check on the new DJ, he recalls. And one day when he left work, police were waiting outside.

Sotelo was detained and released pending a hearing. He went back home, told his father he was on vacation, and started picking up aluminum cans again. Months later, he went to San Francisco for his hearing. The judge listened to his story, expressed sympathy, but said, "You still have to go back."

As police were about to lead him away hours later, a clerk walked up to Sotelo and said, "Here's your work permit." He was told to stay in Sacramento. "Be careful. We're going to keep an eye on you."

A year passed before Sotelo set foot out of Sacramento. He says he never told his family that he was almost deported. "I told them that I was working so hard that I couldn't take a vacation."

These days, with the newfound success, that old lie is his new truth. Piolin is always working, even now, at 9:30 on a Friday night. El Circo, the Mexican circus, is in L.A. He's a headliner. His fans are waiting when he steps out the van.

"Piiiiiiooooooolin!" the children yell. Dust kicks up as mothers drag them over for pictures. Digital video cameras come out, followed by digital cameras, and finally, camera cellphones. Sotelo stops for almost every one of them, at least 200, mostly immigrants like him, many illegal.

Under the big top, his act, a comedy classroom skit, flops, mostly because it's plain not funny.

But no one gets bigger applause during the curtain call -- not the hilarious clowns, the death-defying acrobats, the nimble teenage juggler, or the stunningly beautiful sword balancing ballerina -- than El Piolin.