SAN FRANCISCO, FEB. 14 -- Megan O'Neill didn't have any change for the subway. Judeann Conry offered her a lift. Together, the two law students rode a motorcycle from Berkeley over the Bay Bridge to San Francisco -- the beginning of a journey into a loving, two-year relationship that became official today.

The couple ditched school, plopped down $35 and, with much hugging and kissing, became domestic partners.

Translation: "It says we love each other," said a beaming O'Neill.

It was San Francisco's Valentine's Day gift to its gay community, which has been struggling for a decade to win legal recognition short of marriage for committed lovers, gay and heterosexual. The Board of Supervisors approved the nation's first domestic partners law nine years ago, but the measure, versions of which have since been adopted by other cities, was vetoed by the mayor. It was finally approved by voters last November and timed to go into effect on that most romantic of winter days.

The office of the Registrar of Voters opened an hour early, at 8 a.m., today in the baroque splendor of City Hall, where scaffolding and gaping cracks attest to the 1989 earthquake. Commitment seekers, some in matching tuxes, others in his-and-his black leather ensembles, didn't pay any attention, holding hands and stealing looks at one another.

"Straight ahead," a volunteer directed a couple as they walked into City Hall. "No, I don't mean that."

"Gaily go forward," suggested someone else, perhaps more appropriately.

Two hours after the office opened, more than 50 couples -- including a handful of heterosexual pairs -- had signed up. During that time, fewer than half that many people took out marriage licenses down the hall.

The crisp white certificate with the faint mauve seal of the city and county and the bold, no-nonsense DOMESTIC PARTNERS lettering is basically a declaration that two people love and support each other. It doesn't give property rights or the other perks of marriage, but will entitle city workers to health benefits later this year if approved by the Board of Supervisors. Private employers might follow suit.

O'Neill and Conry plan to frame their certificate and mail copies to their friends and parents. Well, maybe not O'Neill's dad. He doesn't understand.

But it's nice that officialdom finally does.

"It says a lot personally," said Conry, 24. "We're two people who are in love. It's seeing us as people, not just the other or some abomination."

Those of the more activist frame of mind see it as a landmark step on the way toward state-sanctioned gay marriage. A bill to that effect is being introduced into the state legislature this term, but is expected to sink.

"It's about as symbolic as moving from the back of the bus to the front," said Jean Harris, an aide to Supervisor Harry Britt, who authored the partners legislation. "We're not just dying of AIDS, we're having families," she said. "It means I exist."

Walter Rosenthal and Larry May have existed together for eight years, sharing everything from a house to a checking account. Today it was a piece of paper, as romantic in its own way as the cards and flowers they gave each other last year.

"It felt like we're getting married," Rosenthal said. "It redefines family."

That expanded definition is one that has been a long time coming for people here.

During the 1987 Gay and Lesbian March on Washington, Christmas Leubrie and Alice Heimsoth exchanged vows in front of the IRS building to protest the country's unwillingness to allow same-sex marriage. Both were active in the long fight for the law in San Francisco.

Today, wearing the same lace and flowers, after six years together, they finally got the blessing of the city.

"I feel so damn official today," exulted Heimsoth, as she embraced and kissed her partner. "This is great."

"I think I realized early on that this was the woman I wanted to spend the rest of my life with," Leubrie said.