More than a decade after charter schools became legal in Pennsylvania, it is safe to say the schools, once considered experimental and still sometimes controversial, are here to stay.

About 64,000 students are enrolled in 126 charter schools statewide, and about 20,000 are on charter school waiting lists, according to the Pennsylvania Coalition of Charter Schools.

Nearly half of the schools are in Philadelphia. But parents of Western Pennsylvania students -- including 2,355 children living in Pittsburgh -- also have chosen charter schools, which can be bricks-and-mortar buildings or cyber schools.

Their staying power will be in evident this week as the Pennsylvania Coalition of Charter Schools, a statewide advocacy and support organization, conducts its state convention at the Pittsburgh Marriott City Center, Uptown. The meeting, which began yesterday, runs through tomorrow and is expected to attract more than 1,000 people.

Charter schools are public schools, chartered by school districts but run by separate boards. They are open to all residents of the state at no charge, with the home school districts paying a fee set by the state.

Cyber charter schools use the Internet to provide education to students anywhere in the state.

Timothy Daniels, executive director of the coalition, considers Pennsylvania to be the leader in charter schools in the Northeast.

The Center for Education Reform, a national advocacy group, ranks the state's charter school laws as 12th best among 40 states and the District of Columbia. It figures that Pennsylvania ranks seventh in total charter school enrollment.

Charter schools hit the national scene in 1991 in Minnesota, but they didn't become legal in Pennsylvania until 1997.

Pittsburgh's first three charter schools -- the Urban League of Pittsburgh, Manchester Academic and Northside Urban Pathways -- opened the following year. There are now six based within the city, and another one, the Environmental Charter School at Frick Park, is scheduled to open this fall.

City residents also attend 16 charter schools outside the city.

"One indisputable fact is people vote by where they go," said Rick Wertheimer, chief executive officer and principal of City Charter High School, Downtown, now in its sixth year with about 520 students. "We fill up faster and we have waiting lists that are larger than we've ever had."

At Northside Urban Pathways Charter School, Downtown, which has about 300 students and a waiting list, Chief Executive Officer Linda Clautti said, "I think people were very skeptical about what would happen, if they would work and succeed. Here we are 10 years later and they just seem to be proliferating all over the place.

"I think most parents are more aware of what a charter school is, how to apply for a charter school and see the value of having a smaller environment and what happens to their children."

Esther Bush, president and CEO of the Urban League of Pittsburgh, whose charter school in the East End has about 230 students and a waiting list, said some local decision-makers are "still warming up" to charter schools.

Ms. Bush said charter schools and regular public schools both have roles to play.

"I will always be an advocate of traditional public schools basically because that's where the majority of the kids are," she said. "At the same time, those same kids need choice."

Pittsburgh Public Schools Superintendent Mark Roosevelt said the state charter school law is written so that "it almost makes you by necessity adversarial."

He said he wants to develop "a more collegial relationship" with charter schools in which they share resources and keep in mind they all have the goal of serving the city's children.

Last month, Mr. Roosevelt and charter school leaders met at the Pittsburgh Foundation office to discuss the Pittsburgh Promise, a college scholarship program for city school students that was extended to those in charter high schools.

Charter schools and traditional public schools sometimes find themselves at odds over money.

A school district must pay for each resident who goes to a charter school. Up to about 30 percent of those payments may later be reimbursed by the state.

Pittsburgh Public Schools figures the district's charter payments this school year exceed $28 million, and, if history repeats itself, it will get about $8 million back from the state.

Pine-Richland Superintendent James Manley said he thinks competition and choices are good, but the way charter schools are funded hurts school districts. He said they have to pay but can't save money when the number leaving is scattered throughout a district.

"Whether you have 15 students in a room or 25 in a room, you're still paying for that teacher, the lights and all other kinds of things," he said.

Payments to cyber charter schools have been particularly controversial because some people think they should cost less to operate. Cyber school leaders say their schools also have bills to pay.

Legislation that would reduce payments to cyber charter schools has been introduced in the state House. The Pennsylvania Families for Public Cyber Schools will rally May 13 on the steps of the state Capitol to highlight cyber school needs.

One of the state's first cyber schools opened in 2000 in Midland, Beaver County. Now called the Pennsylvania Cyber Charter School, it has 7,500 students from most school districts in the state.

Nick Trombetta, CEO and founder, said that at one point as many as 75 percent of school districts refused to pay for their students, but now that is down to about half. In those districts, the schools file with the state, which ultimately takes the fees out of school district subsidies.

The state Department of Education makes deductions from subsidies of about 250 of the state's 501 school districts for payments to about 30 charter schools, according to spokesman Michael Race.

Dr. Trombetta said in some districts charter schools are "embraced as godsends and in other cases they're dreaded, they're looked down upon" by school district leaders.

"The fact is we exist," he said. "The important thing is we serve families who need and want the service."

Dr. Daniels said charter schools are held accountable for results, and seven in Pennsylvania have closed.

He thinks the competition is good for both regular and charter schools, likening it to competition among airlines.

Jeremy Resnick, executive director and a founder of Propel Schools, which operates four charter schools and will open a high school this fall, has been involved in the charter school movement since before the law was passed, first directing the Charter School Project at Duquesne University and then helping to found Northside Urban Pathways.

He said some school districts have adopted full-day kindergarten after a charter school did so, and online learning in traditional schools has increased because of cyber charters.

"People may have mixed feelings about cyber schools, but that's clearly an innovation being led by charter schools," he said.

Nationwide, charter schools have "shaken things up to some degree," said Jeffrey Henig, professor of political science and education at Columbia University and author of "Spin Cycle," a book on how research is used in charter school policy debates.

Dr. Henig said the quality of charter schools varies widely nationwide and that research on their success is "very mixed."

While some individual schools are doing well, he said, "charter schools are certainly not surpassing in the aggregate traditional public schools. There's a slight evidence they may be doing better the longer they're around."