It's love on the rooftop of a moving taxicab.

One hundred yellow taxis have been set aside to drive around New York City on Valentine's Day bearing digital love messages for $25 a pop.

"Ken Martin Rocks My World, Melissa," says one woman's electronic billboard to her beloved.

From midnight to midnight, each love missive flashes about five times an hour, a few seconds at a time.

All it takes to say "I love you" is a telephone call to Adapt Media, a company that owns a computer gadget linked to the electronic billboards on taxi roofs.

Usually, the taxis flash more mundane things like sports scores and advertising. On Sept. 11, the cabs broadcast emergency numbers and information.

Now they're pitching woo.

The boxes on cabs contain a geographic positioning gadget that locates the moving vehicle anywhere in the city via a cellular modem. That means a client can specify that their Valentine's Day message should pop up when a cab is in a certain area, like the intended target's neighborhood.

For an extra $25, the company e-mails a photograph of the display to the beloved.

Adapt was founded in 1999 by Eyal Cohen and Danny Bar-On, "to bring the Internet to auto advertising," says Baruch Katz, the company's head of technology. Taxi owners get an extra $125 a month to have the display on their roofs.

Erez Gati, who takes phone orders for the messages and enters them on a desktop terminal from a building on Manhattan's West Side, expects to stay busy Thursday.

Gati's own messages "are going to a few girls," he jokes.