Non-US citizens, coming to Puerto Rico to visit, work, or that are looking to immigrate will face the same requirements as visiting one of the states in the United States. Puerto Rico is a Territory or Colony of the United States so all federal laws and immigration requirements are the same.
Below are some links for the information you will likely need related to coming to the US.
One warning, Puerto Rico official language is Spanish, while the rest of the mainland US language is English.
Links below are from USA forum: http://www.expat.com/forum/viewforum.php?id=448
United States Nonimmigrant Visa Guide - Please READ
Finding a job and work sponsorship in the USA
** Puerto Rico has an unemployment rate around 11.5% while the overall unemployment rate for mainland US is around 5% or less. Chances of finding a job or sponsorship will be lower due to the unemployment. Also most jobs will require you to be able to speak Spanish, but not all.
ATTENTION: USA Entry/Exit History Now Available Online
WARNING: Sponsorship/Financial Assistance for US Visa and Visa Lottery
All the above links are from the USA forum and were copied here for your convenience, I can not determine their accuracy.