Mobile-Phone Users View Ring Tones as Worthwhile Form of Self-Expression.

If Kaiser Labidi is waiting for an important call, he'll set his cell phone to the peppy theme from Inspector Gadget. If he's on a date and wants to impress a woman with his flair for romance, he'll opt for Celine Dion's "Have You Ever Been in Love."

"Ring tones mean a lot to me," says Labidi of Winter Park. "It shows what kind of person you are."

Labidi, 24, downloads about one new song a week for $1.50 each, which he considers a small expense for self-expression. Millions of cell-phone users evidently agree with him, which is why phones these days sing more often than they ring.

In the past, most consumers cared most about the appearance of their cells -- they wanted the sleekest and smallest possible phones.

Now, as wireless technology offers radio-quality sound, sight has become secondary to sound for many.

Downloadable ring tones became available in the United States about 18 months ago, and their popularity has been "almost explosive," says Adam Zawel, an analyst with the Yankee Group, a research and consulting firm in Boston.

American consumers spent $80 million on ring tones in 2003. That number is expected to jump to $140 million this year -- and $1 billion in 2008, according to the Yankee Group.

Ten million Americans have downloaded a ring tone at least once. Worldwide, consumers spent $2 billion on ring tones in 2003, Zawel says.

Most tunes cost between $1 and $1.99 and can be purchased either through the wireless companies or on ring-tone Web sites.

Audrey Bellamy, 20, coordinates songs with certain callers, so their ring tones provide a screening service.

For her boyfriend, it's Beyonce's "Crazy in Love." For her brother, a big 50 Cent fan, it's "In Da Club." An ex-boyfriend has the dubious honor of 50 Cent's "Wanksta," just so Bellamy knows not to pick up the phone.

"Some people I don't want to talk to," says Bellamy, a student at the University of Central Florida.

Industry experts say the biggest growth has been among teenagers and young adults, who enjoy the novelty of customizing their phones.

"Young people like to personalize whenever they possibly can," says Max Valiquette, president of Youthography, a youth-market consulting firm in Toronto. "Sometimes that means you scratch the name of your favorite band into your desk at school; sometimes it means you want to have a downloaded cell-phone ring tone."

The most popular downloadable songs include 50 Cent's "In Da Club" and OutKast's "Hey Ya," industry experts say. It's not unusual for users -- particularly teenagers -- to change their ring tones weekly in deference to the latest hits.

But older users look beyond the latest hits for a more classic repertoire.

"There's an expectation that ring tones will mirror your music catalog," Valiquette says. "They shouldn't just be your favorite songs right now."

Ring tones can include everything from the opening chords of Guns 'N Roses' "Sweet Child O' Mine" to Michael Jackson's "Beat It."

Many ring-tone aficionados have no shame, because their phones' tones are a socially acceptable way to be unapologetically cheesy. For instance, many consumers gravitate toward one-hit wonders, such as A-Ha's "Take On Me" and Right Said Fred's spoof "I'm Too Sexy."

Shifting from the dork side to the dark side, Khrystal Dickens, 18, favors The Twilight Zone and Nightmare Before Christmas themes.

"Some people say my rings are annoying," says Dickens, a Tennessee high-school student who visited Orlando in March. "But others sing right along."

Other users wallow in childhood nostalgia: 22-year-old Frederick Parisi's phone alternates between the Scooby Doo and Batman themes.

Kevin Khandjian, an 18-year-old UCF student, uses ring tones to screen calls, especially "the annoying T-Mobile ring tone" for a girl "who thinks we're friends." He takes her calls only "if I'm totally not doing anything."

Although the ring tone craze is primarily a young demographic trend, Chuck Hamby insists that "older folks" such as himself -- he's 43 -- are also ring-tone crazy.

For instance, when Hamby's boss calls, Hamby's phone blares the theme song from the spaghetti Western movie The Good, the Bad and the Ugly.

When Hamby's wife calls, his phone plays the love theme from The Godfather.

And when a certain annoying person calls (Hamby, a Verizon spokesman, would not say who), his phone warbles that Wizard of Oz tune, "If I Only Had a Brain."

Clearly, age is no impediment to fun with ring tones. Of course, the over-40 set is more likely to download "Hey Jude" than "Hey Ya!"

Then again, kids will surprise you. Colonial High School student Marilyn Pantoja, 16, has a cell-song collection that includes classics such as "It's Raining Men," "Stop! In the Name of Love" and the perennial favorite "Let's Get it On."

Besides the opportunity for self-expression, distinctive tones offer practical benefits too. It used to be that when a cell phone rang, everyone in the room would dive into their purses and pockets. Now, a ring tone can immediately identify a phone to its owner.

Well, in theory, anyway. You never know -- everyone in the room just might be waiting for OutKast. So when you hear the familiar strains -- My baby don't mess around/Because she loves me so/And this I know for sure -- for sure, you won't know whose phone is singing.