Once upon a time, in a far-off kingdom called Wyckoff, New Jersey, there lived a band of three young brothers—squeaky-clean moppets who loved girls, God and rocking the heck out, not necessarily in that order. They performed as part of an antidrug school tour and opened for the Cheetah Girls. Life was good. Then one day Disney came calling, plucking the brothers from obscurity and turning them into a tight-suited, squeal-inducing adolescent phenomenon. Hear the cry go up throughout the land: Jonasjonasjonasjonasjonas!

In case you haven’t encountered a junior-high student in the past 18 months, the Jonas Brothers are basically like the Beatles, only more talented and sooo much cuter. An opening slot on last year’s Hannah Montana tour launched them into the tween-pop stratosphere. Now, with the full weight of the Mouse marshaled behind them, the cross-branding has reached saturation levels: There’s a behind-the-scenes reality show, a made-for-TV movie (Camp Rock—think High School Musical with s’mores) and nonstop radio airplay, not to mention a 3-D concert flick scheduled for 2009 and J.O.N.A.S., a prime-time series on the Disney Channel. Zac Efron must be so pissed.

So just who are these few, these happy few, these Jonas brothers? Nick, 15, is the prodigy; slender and baby-faced, with a mop of chestnut curls, he writes most of the songs and sings most of the choruses, where his nasal, post-pubescent keen has maximum sing-along impact. Joe, 19, is the handsomest Jonas; his duties include singing and having great hair. And 20-year-old guitar player Kevin, the Cooper Manning of the family, seems happy just to be included. (There’s one more brother, 7-year-old Frankie, whom fans call Bonus Jonas. Look for his debut circa 2015.)

Like all teen stars, the brothers’ burden —the Jonas onus—is having to appeal to 12-year-olds while not alienating the moms who drive them to shows. The JoBros—who were first groomed by the same record executive who discovered Hanson—play their own instruments (though not as well as their backing band plays theirs) and write their own songs, for which they surely deserve credit from people concerned with such things. They love the Beatles and Elvis Costello, and their zippy pop rock succeeds on good cheer and a vaguely punkish élan. Think My Chemical Romance with fewer issues, or a slightly girlier Avril Lavigne. First single “Burnin’ Up” is a Maroon 5–worthy pool-party jam, and “Lovebug” boasts a delightful little melody and the rawkinest guitar solo Radio Disney has heard. Ever since the reign of Britney and Backstreet, the best tween-pop has taken its cues from hip-hop and R&B. The JBs, though, are reintroducing recess to rock.

The Jonases started as a Christian band (their dad/comanager is a former minister), and they carefully embody religious values without explicitly flaunting them. In their songs about girls—and they’re all about girls—the Jonases prize honesty, commitment and fidelity. They venerate family (JoBros before hos!) and don’t tolerate manipulation. On rare occasions when they screw up (e.g., “Sorry”), they’re totally contrite. “A Little Bit Longer,” a plaintive ballad guaranteed to reduce their audiences to human mascara puddles, is nominally about Nick’s battle with diabetes, but works just as well as a breakup song. Low blood sugar never sounded so poignant.

Becoming a teenager is confusing and scary. The Jonases offer a friendly road map. Much has been made of their “purity rings,” symbolizing a pledge to stay celibate until marriage; for some fans, it’s a promise as simultaneously enticing and frustrating as a box of cookies on a high shelf. For all the hormone floods they trigger, when it comes to sex (or, in this case, holding hands at the movies), the JBs are never the aggressors. For young girls learning to navigate their own sexuality, there’s something comforting about a group so non-threatening and square. Yes, the Jonases are squishy, vanilla and too sweet. But so is an ice-cream cone. And ice-cream cones are freakin’ delicious. Especially when they come with a cherry on top.

Download “Lovebug,” “Pushin’ Me Away,”“A Little Bit Longer”