A grateful mayor is delighted that the Republican Party picked New York as the site of the 2004 presidential convention next September, and no wonder. Mayor Michael R. Bloomberg expects the event to draw 50,000 visitors and generate $150 million for the city.

But the motley Manhattan population of liberals, feminists, performance artists, environmentalists and self-styled anarchists who oppose the Bush administration for one reason or another are already in full cry. Plans to disrupt the convention are in motion a year in advance.

"We know what the Democratic candidates and people who dislike the Bush administration stand for, and their messages sound very similar," said Republican National Committee spokeswoman Christine Iverson yesterday. "When there's no positive leader and no positive agenda for the country, people resort to pessimism," she continued. "The messages from Howard Dean, John Kerry and others sometimes sound like messages from these groups. This is just par for the course."

Two grass-roots organizations are at the center of the protest. RNC Not Welcome says the convention is funded by "a host of corporations, millionaires and billionaires" and hopes to prove that the city of New York does not support the event. "Why host a convention in September? Why New York?" asks Counter Convention, another group. "By exploiting our grief and trauma from September 11th, the right wing intends to further their regressive political agenda."

Both are among the motley activists who staged a bike and roller-blading protest Saturday through the streets of Manhattan, intent on "disinviting" the Republicans. "How about not welcoming the DNC too, wherever they're going to be?"asked one eager participant in a discussion of the event yesterday at the New York Indymedia Center Web site(www.nyc.indymedia.org).

The groups will also stage a mask- and costume-making session for dramatically inclined activists in Manhattan this weekend, along with a workshop for "street medics" who anticipate violence. The festivities will culminate in a public party on Union Square to declare it a "Patriot Act Free Zone."

In addition, United for Peace and Justice ¹Äî a New York-based group that has also organized protests against the World Trade Organization, the war in Iraq, nuclear weapons and revised Federal Communications Commission media-ownership rules ¹Äî has declared Aug. 29, 2004, as "The World Says No to Bush" day. The protest event will coincide with the Republican convention, scheduled for Aug. 30 to Sept. 2 in Madison Square Garden.

But convention planners are already ahead of the game. In early July, the gathering was classified a "national special security event" by Homeland Security Secretary Tom Ridge, making it eligible for protection by the FBI and Secret Service, along with state and local law enforcement.

Meanwhile, the variety of protest groups keeps growing, at least according to the Counter Convention Web site (www.counterconvention.org), which has tallied a roster of those who oppose the Republican convention. They include, among others, the Female Species Collective, the Socialist Party USA, North Brooklyn Greens, Not in Our Name, Electronic Disturbance Theater, ACT UP, Food Not Bombs, Mad Anarchist Baker's League, and something called Time to Clean Up This Directory (TTCUTD). In its public message, the TTCUTD noted, "It would be useful to moderate this directory so people organizing against the RNC can do that without stupid spam listings."