[DevilsWin]

Sorry, but it is illegal., except in certain circumstances.
There are and have been sanctions against Cuba for many years.

Here's some info regarding travel and sanctions with Cuba:
(answers the question as to how Matt Lauer could travel there)

US and Cuba Travel Policies

• Introduction
  
• Overview of Travel Regulations
  • What are "Travel-Related Transactions"?
    
  • What role does OFAC have in dealing with the Cuban Sanctions?
• General Licenses
  • Professional Research and Professional Meetings
    
  • Officials of the U.S. Government, Foreign Governments and Certain Intergovernmental Organizations
    
  • Journalists

Restrictions on travel to Cuba are authorized by the Trading with the Enemy Act of 1917, which grants the power to prohibit financial transactions in time of war. Citing national security concerns, the U.S. government imposed an economic embargo on Cuba in 1961. In July 1963, the U.S. Treasury Department released the Cuban Assets Control Regulations, which codify the essential elements of the economic embargo against Cuba. Such elements include a freeze of all Cuban-owned assets in the U.S., a prohibition on all non-licensed financial and commercial transactions between Cuba and the United States and between Cuban and U.S. nationals. The financial prohibition includes the spending of money by U.S. citizens for travel to Cuba, which essentially creates a travel ban on the island for all non-licensed U.S. citizens.
The embargo regulations have been eased and tightened several times over its forty year history. In 1977, the Carter Administration removed all restrictions on travel to Cuba. However, the Reagan Administration reinstated an even stricter travel ban in 1982 and travel restrictions on most U.S. citizens traveling to Cuba continues to this day.

He was given a journalistic license