NEW YORK - Gay couples will be able to marry in New York state from July 25, and New York City hopes to woo them with an 'NYC I DO' campaign as officials prepare for an expected deluge of weddings.

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An estimated 66,000 gay couples will marry in New York state within three years, adding about $284 million to the state's economy, according to a report by the Independent Democratic Conference, a separate state caucus of four Democrat Senators.

Couples from all over the United States and abroad can start applying for marriage licenses from July 5. The $35 license must be obtained before any couple can get married in New York state.

"We will gear up for a larger number (of weddings)," New York City Mayor Michael Bloomberg told reporters on Monday, speaking of the city's preparations.

New York will become the sixth and most populous US state to allow gay marriage. State senators voted 33-29 on Friday to approve marriage equality and Governor Andrew Cuomo, a Democrat who introduced the measure, immediately signed it into law.

The city's marketing and tourism group, NYC & Company, said it was developed an 'NYC I DO' campaign to make it the No. 1 destination for gay couples.

"We anticipate that the campaign, set to launch soon, will create hundreds of millions of dollars in additional economic impact to the city's $31 billion tourism industry," said NYC & Company Chief Executive George Fertitta.

Some organizations have already started their own publicity, such as the Museum of the City of New York near Manhattan's Central Park, which tweeted on Monday: "Rent space at the Museum for your gay wedding! We throw a great party!"

NYC & Company also has a list of hotel offers like the "Love Has No Boundaries/Born This Way" package at the Le Parker Meridien and "The Right to Unite" special at W New York.

Bernadette Smith, founder of the Gay Wedding Institute, which plans weddings, tweeted: "My phone and e-mail are blowing up with wedding vendors looking for NY gay wedding business and people looking for jobs!"

Connecticut, Iowa, Massachusetts, New Hampshire, Vermont and the District of Columbia allow same-sex marriage, and Delaware, Hawaii, Illinois and New Jersey have approved civil unions. The first legal same-sex marriages in the United States took place in Massachusetts in 2004.

In California a judge last year overturned a ban on gay marriage, but no weddings can take place while the decision is being appealed. It could set national policy if the case reaches the US Supreme Court.

But gay marriage is banned in 39 states.