Obama says ready to listen to South Americas leaders

* Venezuela's Chavez presents Obama with left-wing book

* Obama offering help on energy, fighting arms and drugs

By David Alexander

PORT OF SPAIN, April 18 (Reuters) - U.S. President Barack Obama sat down with South American leaders on Saturday, saying he was ready to listen and learn after promising an era of more regional cooperation and a new start with communist Cuba.

At the start of the Fifth Summit of the Americas in Trinidad and Tobago, Obama is a partnership to develop energy resources, tackle the dangers of climate change and counter the threats of arms- and drugs-trafficking threatening the hemisphere.

"I have a lot to learn and I am very much looking forward to listening and figuring out how we can work together more effectively," Obama told reporters before going into a meeting with key leaders from South America ahead of the summit's plenary sessions in Port of Spain.

Shortly before the summit's opening session late on Friday, Obama shook hands with Venezuela's President Hugo Chavez, a strident critic of Washington's policies and a leftist standard-bearer for anti-U.S. sentiment in Latin America.

As Saturday's meeting started, Chavez, following up on his friendly greeting to Obama, presented the U.S. leader with a book, "The Open Veins of Latin America," by left-wing Uruguayan writer Eduardo Galeano.

The U.S. leader received the gift with a smile.