By 7:30 a.m. yesterday, 2 1/2 hours before the opening of Tysons Corner Center, a long line of anxious youngsters already had formed outside the mall.

Tickets to a rock concert? A special showing of scenes from the next "Star Wars" movie? No, these pre-teens and their bleary-eyed parents had come in search of stars with names like Blastoise, Charizard and Venusaur.

If those names don't sound familiar, then you haven't been around anyone between the ages of 5 and 12 in the last several months. They are but three of 151 exotic-looking creatures--"pocket monsters"--in the Japanese game called "Pokemon," one of the biggest toy crazes ever to sweep America.

The Pokemon phenomenon started with a hit cartoon, which led to video games, comic books, an assortment of toys and now trading cards. It was the cards that drew yesterday's throngs to Tysons, one of the stops on a Pokemon "trading card game tour" of 19 cities.

Much of the mall's lower level had been transformed into a kind of Pokemon heaven. Here was a car customized to resemble Pikachu, one of the most popular Pokemon characters. At various stations, children could play the trading card game, get game pointers from experts or have their picture taken next to a giant Pikachu trading card. Or they could ignore the stations and just trade cards with other young Pokemon addicts, many of whom had come with their card collections tucked inside notebook-style binders.

"This is so cool. It's better than I even imagined it would be," said a breathless and wide-eyed Joel Frohlich as he waited in line to have his picture taken next to Pikachu.

Joel, 9, who lives in Oakton, waited in a two-hour line for a chance to sit down and learn to play the trading card game.

"I didn't exactly know what I was getting into," said Julia Frohlich, laughing as she watched her son play.

In another line, Kyle Coates, 7, screamed as if he had struck gold. "I got a Blastoise!" he squealed. "I had a Venusaur and this kid said he'd trade me for it!" Kyle, his mother and another family had driven to Tysons from Stephens City, Va., near Winchester.

Mark Wienhold and his two sons had come from Maryland's Eastern Shore. They spent the night at the home of Wienhold's mother in Leesburg, thinking they'd shoot over to the mall about 10:30 or so.

Bad idea. Shortly before noon, the boys were still about three dozen kids away from the Pokemon Central registration table.

"This is absolutely insane," Wienhold sighed. His mother, Pat Wilburn, concurred.

"We've only been here about an hour and a half, but it feels like we've been here all day," Wilburn said.

Gaithersburg siblings Natalie and Adrian Pitts decided to forgo the lines to do some serious trading with some of the other children. Adrian, 10, already has about 800 trading cards. Natalie, 13, has about 200.

Adrian couldn't believe his luck when he found two prized holographic cards in two packages of cards he had just purchased from the store Game Keeper, one of the sponsors of the event.

"You know, the stats say you usually only find one holographic card in every three packs you buy," he gushed.

Mall officials estimated the attendance at about 7,700 and were expecting similar numbers today, when the event continues between 11 a.m. and 4 p.m. Next weekend, the "tour" stops at Towson Mall in Baltimore.

"They've been needling me to death since they heard about this a few days ago," said Sara Pitts, Natalie's and Adrian's mother. By mid-morning, her children had started asking her about returning to Tysons today.

"You know, I think I'm going to come back Sunday and get some really good trades," Natalie said. She cast a pleading glance at her mom, who was actually weighing the idea of a return trip.

CAPTION: Pokemon fans from across the region flocked to the lower level of Tysons Corner Center, where they learned to play the trading card game from experts.

CAPTION: Christopher Reeve, 9, of Alexandria, played the game, a spinoff of a Japanese cartoon.