At last - a swell new musical, "Annie," funny, tuneful, zestful and clever.

It will be at the Eisenhower through April 2 and if you don't rush for tickets, you'll have to go to New York later.

Inspired by "Little Orphan Annie," the Harold Gray comic strip, the new show is that magic mix that's been eluding our musical creators for too long. Martin Charnin, who did both the lyrics and direction, has an unbelievably grand cast headed by 13-year-old Andrea McArdle, a perfect little Annie. Like Daddy Warbucks, you'll want to wrap her up and take her home.

The musical's major making his theatrical bow. His book by passes the Daddy Warbucks we are familiar with - the one who might have been one of those Union League characters in The New Yorker's Peter Arno cartoon captioned: "Let's all go down to the Trans-Lux and hiss Roosevelt." Meehan'sWarbucks is so genial with FDR that he gets the President's aid in tracking down Annie's parents.

That is all "Annie" is about, a little redhead's search for the parents who left her at New York's municipal orphanage 11 years earlier. Running away doesn't help, but Daddy Warbuck's Christmas hospitality to an orphan he'd hoped would be a boy serves to soften his heart. With all his millions, can Warbucks find Annie's parents?

Meehan more than compensates for his Warbuck's revisionism with his characterization of Miss Hannigan, an outrageous noodle in charge of the municipal orphanage of females.

Given Meehan's material, Dorothy Loudon embellishes the Miss Hannigan role with a madness embodying the style of comic strips. When she reacts to thespirited girls confined to her care, she reacts big, then freezes. When she wants to scream, she screams as though from a cartoon ballon. Gasping on cigarettes, her stomach lining all but visibly shredded from an ever-present bottle of booze, her arches under constant attack by her loathed "Little Girls," Loudon creates a rare, oddly likable monster.

Her distaste for her jailbird brother melts only when he and his wife jubilate to her about "Easy Street," a whammy Act I show-stopper in true 30s style through Philip J. Lang's orchestrations of composer Charles Strouse's belting melody.

Meehan's plot devices include a radio studio, where NBC is presenting Oxydent's Hour of Smiles with Donald Craig's gooey tenor, the chirping trio of Boonie, Connie and Ronnie and a gum-chewer with applause card. This has been mocked before but never so deftly as Charnin has staged it. Composer Strouse's spoof is so exact that "You're Never Fully Dressed Without Smile" seems the real thing. When the orphanage girls give it their version, you'll whoop for joy.

All is not perfect, however. There's a serious dip about one third into Act II which requires splicing. It's not the fault of Reid Shelton, a Daddy Warbucks with the sweetest voice this side of heaven.

"I turned a million dollars into 100 million. In those days," Shelton sighs sweetly,"that was a lot of money."

We miss the divine Miss Hannigan's spice as Act II's sugar slows the pace. Or it is a Peter-Gennaro dance we need? Whatever, I'm confident that, having done so brilliantly with the rest,"Annie's" creators will nurture this fallow patch these next three weeks.

Easier to smooth out in performance will be the sliding panels David Mitchell has devised for New York of the Depression. Their glide suggests cartoon panels, and when they stop lumbering, they'll be a delight.

Composer Strouse and Iyricist Charnin are in fine fettle, further insuring a New York success with the proudest song salute it's had in years, "N.Y.C." If New Yorkers aren't roused by this paean, choreographed by Gennaro, Big Mac is truly down the drain.

By coincidence, this 44th anniversary week of FDR's inauguration is reflected in the score,"Tomorrow" and "A New Deal for Christmas," the first a song that will be widely popular, the second likely to join the Yule standards.

If all this sounds like more of the nostalgia diet, bedisabused. There's a viewpoint I can only call tart optimism. In the show, FDR aides Hopkins, Ickes, perkins et al are fed up with FDR's favorite line on fear. Concept and style capture cartoons as they might be if they came to life.

McArdle, Loudon and Shelton aren't the only ones in the east. There's a lovely singing secretary by Sandy Faison and a rousing singer, Laurie Beechman, for "We'd Like to Thank You, Herbert Hoover" and her Frances Perkins. There's quick delineation by Robert Fitch, as Hannigan's brother, and Barbara Irwin, who admits that her Lily St. Regis is named for the hotel. The six girls of the orphage will enchant you, and Sandy has been perfectly cast, rescued, I'm told, from a dog pound just before getting the needle.

"Annie" and all in it are delights. Now to repair that second - act pothole.