Call them the littlest activists. A group of middle school girls, angered by a smokeless tobacco billboard near their school, took on the giant Philip Morris tobacco company.  And they won.
    The 13 girls, seventh and eighth graders at Horace Mann Middle School in San Francisco, wrote a letter to the firm, charging it with violating its own policy of not permitting tobacco ads within 500 feet of school grounds.  The smokeless tobacco billboard was 146 feet from the school grounds, they wrote.
    "We feel it's unfair to us that you are targeting young people like us," they wrote to the company's Chief Executive Officer.  "We are Chicana, African American, Irish American, Latina and Filipina young women of San Francisco."
    They collected signatures for a petition and sent copies of their efforts to Mayor Jordan and Supervisor Angela Alioto.
    The company did not respond to the letter. But the sign came down.
    "They shouldn't be targeting us with their ads," said 13 year old Mayra Morell.  "They should target people who're old enough to make stupid decisions...like smoking."
    Thursday the girls had a victory celebration, with a "Dunk Joe Camel" booth at the school's annual festival.
    For Cindy Manriquez, 12, who nagged her father for years before he kicked the habit, it was very important to see the advertisement come down. "Those ads make it seem like it's OK to smoke...and it's not," she said.
    Joycelyn Bunac, 12, said she just wanted Philip Morris to recognize that it had violated its policy and should do something about it.
    Even fellow student Jeffrey Henderson, who didn't participate in the letter writing, said he agreed with the girls. "It shows that they care about us...and they were willing to take a stand for our health," he said.
    "This is very empowering for the kids," said physical education teacher Mike Beltrean, "and it gives them a chance to be more socially responsible."
    A spokeswoman for Philip Morris in New York said the company did not target people under 18. "And our policy has been that we do not respond to letters written by anyone under 18." she said. The company will send its response to Horace Mann Principal Richard Murphy.
    San Francisco Health Director Sandra Hernandez said the company's letter writing policy didn't make sense because children should be able to have an opinion about their health, and Philip Morris should be willing to respond.
    She said she hoped the children would continue to fight tobacco advertisements. "I think it's fabulous... organizing to maintain a healthy community, and this reflects a tremendous amount of health education effort by the middle school," she said.
    Even as they celebrated their victory, the girls were turning their attention to the ad that replaced the Philip Morris billboard-one for beer.
    "They should put something else up," Cindy Manriquez said. "They just traded one bad ad for another."