Operating for two decades as a small alternative program with just two classrooms, the new Harvey Milk HS officially opens as a stand-alone public school with 100 students in September.

The school, located at 2 Astor Place, is undergoing a $3.2 million in city-funded renovations approved by the old Board of Education in June of last year. It will eventually take in 170 students by September 2004, more than tripling last year's enrollment.

The Hetrick-Martin Institute - the gay-rights youth-advocacy group that manages and helps finance the school in conjunction with the Department of Education - has hired the school's first principal.

In the past, Harvey Milk HS - named after the slain gay San Francisco politician - was assigned an "off-site" supervisor who also oversaw several other schools.

"This school will be a model for the country and possibly the world," Principal William Salzman said in an interview at the facility that will boast a new science lab, 60 laptop and desktop computers donated by IBM, additional classrooms and a new cafeteria.

Salzman, a former Wall Street executive, was most recently assistant principal of guidance and business information technology at Brooklyn's Automotive HS.

Salzman said Harvey Milk will be an academically rigorous school that follows Schools Chancellor Joel Klein's mandatory English and math programs. It will also specialize in computer technology, arts and a culinary program.

"This is a not a touchy-feely situation," Salzman said. "We intend to have 95 percent of our students go on to college. We have a lot of talent coming into the school. We want to steer these kids in the right direction."

State Conservative Party Chairman Mike Long blasted the school as "social engineering" that wastes tax dollars.

"Is there a different way to teach homosexuals? Is there gay math? This is wrong. This makes absolutely no sense," Long said. "There's no reason these children should be treated separately."

Long said there are city and state discrimination laws on the books and that authorities should enforce them to stop gay-bashing.

"What next? Maybe we should have schools for chubby kids who get picked on. Maybe all kids who wear glasses should have special schools. It's ridiculous," he said.

What burns Long most is the $3 million spent on renovations. "Maybe this is one of the reasons the city has no money," he said.

Arthur Larsen, who graduated from the program last month as valedictorian, is thrilled with its expansion into a full-fledged school. "I'm now an alumnus of a real school!" he said. "There's going to be more students. In four years, I want to work here."