PORT OF SPAIN - If President Barack Obama needed a reminder that times have changed in the Americas, his fellow presidents gave him one when Air Force One touched down in Trinidad and Tobago for a regional summit.

Four years ago when his predecessor George W. Bush flew into Argentina for the last Summit of the Americas he was greeted by rock-tossing protesters and an alternative summit led by Venezuelan President Hugo Chavez, raging against the evil empire.

This time, the U.S. president was met by smiles, the cheery clang of Caribbean steel drums and prime ministers and presidents seeking out his autograph. Chavez even told the young U.S. leader, twice: I want to be your friend.

This is the Obama summit, one Brazilian diplomat said.

An observation blimp circled over the conference center in Port of Spain, where a cruise ship housed journalists and white-jacketed police guarded perimeters as Obama and other leaders brainstormed on the economy, energy and security.

Obama had to parry demands to lift the U.S. embargo on Cuba and got a history lesson about U.S. imperialism from Nicaraguan President Daniel Ortega. But the positive vibes surrounding the young U.S. leader were hard to ignore.

Colombian President Alvaro Uribe was one of several leaders who obtained a prized Obama signature. He showed off a scribbled message from Obama: To President Uribe, with admiration.

Barack Obama signed this little letter for me ... I'm going to send this to get framed, he joked with reporters outside the summit conference hall.

At one official photo, Obama chatted easily with leftists like Chavez, who have made America-bashing the heart of their political personalities.

Even an alternative summit was friendly.

In Argentina, Chavez rallied thousands of protesters to rage against Bush and free trade.

But in Trinidad, a small group of demonstrators taking part in a drummit summit played drums, displayed Cuban flags, and hoisted posters carrying images of both Chavez and Obama.

Chavez was greeted as always by mobs of reporters. A scuffle involving journalists crushing to reach the Venezuelan leader prompted summit hosts to briefly restrict media coverage of some events on Saturday.

But Obama's listen and learn approach won over more than a few of the hemisphere's most powerful figures. Chavez presented him with a book by a Uruguayan leftist. It shot to No. 2 on Amazon.com's best-seller list on Sunday.

He's a cool man, St. Vincent and the Grenadines Prime Minister Ralph Gonsalves said before the closing ceremony. He's an intellectual ... he wants to have a fresh start.