"High School Musical": The Phenomenon

It started as just another Disney cable movie. But now it seems every "tweenager" knows the words to "We're All In This Together."

"High School Musical," the fresh-scrubbed film about a teenage jock and a brainiac who shock their friends by auditioning for the school show, has struck a nerve.

Says mom Chrissy Whitelaw: "I think kids like having role models to look up to and enjoy singing along."

More than just an unexpected hit, it's now a global entertainment phenomenon, reports CBS News business correspondent Anthony Mason. The DVD has sold 7.8 million copies and the CD was the No. 1 album in the country last year. There's a live concert tour, a live stage show — even "High School Musical on Ice."

Co-star Vanessa Hudgens spoke about "High School Musical 2" on The Early Show. To see the interview, .

"What's funny is every high school across the nation does a version of 'High School Musical' now. It basically is this generation's 'Grease,'" says Dalton Ross, editor of Entertainment Weekly.

That success has spread in a word-of-mouth wildfire.

"The first night it aired, the texting numbers at all the major cell phone carriers went up during the movie. Kids were texting each other: 'Turn this on,' 'Zac's cute,'" says "High School Musical" author Peter Barsocchini.

Even in its 21st repeat showing on the Disney Channel, "High School Musical" drew nearly 6 million viewers. Not even the Disney marketing machine expected this show would be such a slam dunk.

It's made stars of cast members like Zac Efron, who plays heartthrob basketball captain Troy Bolton. On the cover of Rolling Stone this week, Efron had fans swooning at the premiere of "High School Musical 2."

Ross says that kind of success meant there had to be a sequel.

"Obviously, with those sorts of numbers, you're going to go back to that well and you're gonna get it until there's no water left," says Ross.

The sing-along continues Friday night. This time, with a baseball number, and Disney is banking on a home run.