Porter Traditional School, a Prince William school all of two months old, is designing its traditions as it goes along.

When visitors show up at a classroom, a designated greeter is supposed to come to the door and explain the lesson in progress. But one second-grade greeter covers her face in a fit of shyness as Principal Darci Whitehead takes a visitor to her class.

"I'm scared," she says, giggling but coming no closer.

There are a few rough spots yet to iron out at Porter School in Woodbridge. The public school, which offers the standard curriculum in first through sixth grades this year, is distinguished by its rigorous atmosphere, including a restrictive student dress code and a volunteer work requirement for its students and parents.

It already has developed a strong following; Whitehead said there were waiting lists at every grade level except fifth. Parents still call every day.

The families whose children are enrolled, courtesy of a blind lottery, are paying close attention, Whitehead said. There's pressure to achieve test results similar to Pennington, a similar school in Manassas. Pennington students routinely achieve more than a 90 percent passing rate on the state Standards of Learning tests.

Parents "are watching you," Whitehead said. "But they're also thinking, what can I do to help you?"

Porter, which will add seventh and eighth grades in the next two years and grow to 650 students, is just the newest example of school choice in the county. For the last five years, Prince William has offered students an opportunity to attend out-of-boundary schools at nearly all grade levels.

Prince William gives its students more flexibility in choosing schools than do other area districts. Schools throughout the county offer specialities that focus on such subjects as foreign languages, informational technology, math and science or the arts. Students do not have to take a qualifying test to enroll, as all the programs are provided on a space-available basis.

The numbers of transfer students have steadily increased: This year, 3,209 Prince William students attended out-of-boundary schools, compared with 2,484 last year. Prince William has about 66,000 students countywide.

Anissa Watkins's daughter Jaihna is a two-time pioneer. As a first-grader, she attended Pennington School when it first opened. Now, as a 10-year-old fifth-grader, she has moved to Porter, much closer to home. Watkins says that, as a parent, she loves the school's homework load, the discipline, the dress code and particularly the parent volunteer requirement.

"I love it," said Watkins, who works full time. "I don't feel that it's a burden."

After five years, Superintendent Edward L. Kelly sees specialty programs as an experiment that has worked.

"We've gone past the point where you can say everybody's got to get the same education," he said. "It's almost to the point where high schools are small universities."

Kelly instituted the same transfer policy in Little Rock, Ark., and Rockford, Ill., where he served as superintendent before coming to Prince William in 1987. In Rockford, parents asked to switch schools, and he had to turn them down because of boundary concerns.

"After a while, I thought, 'This is stupid. Why am I fighting this?' " Kelly said.

Specialty schools such as Pennington and Porter differ from the specialty programs. Although specialty programs expand on the standard curriculum, specialty schools offer the same subjects as any other. It is the atmosphere created by the school rules that is different -- and popular.

"It gave us all of the things we liked about the private school environment, but it also gave us some of the academic resources and rigor that Caitlin particularly needed," said Milt Johns (Brentsville), vice chairman of the Prince William County School Board and a former Pennington parent. His daughter is now in ninth grade at Battlefield High School.

Jayne Jones, a Porter parent and head of the fledgling school volunteer program, said she wanted her daughter to attend the school "to protect her a little bit."

"I just thought that she would do better in a smaller school," Jones said.

Kelly said such choices should not be seen as an indictment of the other county schools. "You need to develop reasons for them to stay," Kelly said. He said programs such as an international math and science program at Potomac High School and a math and science program at Rippon Middle School have cut down on what he called "white flight" there. At Potomac, 147 students transferred into the school this year to take part in the program.

Whitehead, formerly the principal of Montclair Elementary, used to feel such choices acutely. "I thought that if I had a child who moved to Pennington, I felt that I had failed that child."

Her opinions have changed. "Some children just need that kind of structure," she said. "That's not a knock."

At Porter school, Andy Anderson teaches, from left, fifth-graders Jennifer Brown, Amrit Kaur, Jayla Collier, Erik Quiroga, Janaye Oliver, Tiana Young, Kealey Cela and Stephen Kelsey.Above, sixth-grader Owais Ghaus helps put up the flag at Porter Traditional, a popular new school in Woodbridge that imposes a strict dress code and requires volunteer work by students and parents. At right, fifth-grader Tiana Young does some independent reading. Andy Anderson, a fifth-grade teacher at Porter Traditional School, works with a small reading group. From left are Jennifer Brown, Amrit Kaur, Jayla Collier, Erik Quiroga, Janaye Oliver, Tiana Young, Kealey Cela and Stephen Kelsey.