? Cuban-Americans on Long Island expressed cautious optimism Tuesday following the resignation of Fidel Castro as president of Cuba.

The ailing 81-year-old Castro resigned as Cuba's president Tuesday after nearly a half-century in power, saying he will not accept a new term when parliament meets Sunday.

The end of Castro's rule - the longest in the world for a head of government - frees his 76-year-old brother Raul to implement reforms he has hinted at since taking over as acting president when Fidel Castro fell ill in July 2006.

"My wishes have always been to discharge my duties to my last breath," Castro wrote in a letter published Tuesday in the online edition of the Communist Party daily Granma. But, he wrote, "it would be a betrayal to my conscience to accept a responsibility requiring more mobility and dedication than I am physically able to offer."

Cuban-Americans on Long Island hope Castro?s resignation signals the start of change in the country. Many of them hope to one day be reunited with family members still in Cuba.

However, their excitement is tempered by skepticism over Raul Castro?s rule. Many believe major changes are still some time away.

That sentiment has been echoed by the U.S. government, which has stated it will not immediately change its policies toward Cuba. The Bush administration has even called Raul Castro a ?dictator-lite.?

Associated Press wire reports contributed to this story.

Additional CNN coverage of Castro's resignation