A citizen of a foreign country wishing to enter the U.S. generally must first obtain a visa, either a non-immigrant visa for temporary stay or an immigrant visa for permanent residence. The type of visa you must have is defined by immigration law and relates to the purpose of your travel.
Non-immigrant Visas - for example for temporary visits for pleasure, exchange programs or study.
Immigrant Visas - for example for permanent residency, marriage to an American citizen or adoptions.
Diversity Visa Lottery Scam - The visa section has noticed a recent rise in email-based scams claiming to notify the recipients that he or she has won the diversity visa lottery. This fraudulent email wrongly leads recipients to believe that their visa will be approved and requests that a sum of money be transferred via Western Union to an addressee in the London. The US government NEVER notifies winners of the diversity lottery by email. Any email that is ever sent by the US government will come from an email that ends in .gov, and not .com or .org. For more information please click here. ( → link to http://travel.state.gov/visa/immigrants/types/types_1749.html)
If you win the diversity visa lottery in the 2011 cycle, you will receive a paper notification in the mail. If you win the diversity lottery in the 2012 cycle, or any year afterward, you will not receive any notification that you have won. Instead, you will have to log in to the same website where you applied to the lottery (http://www.dvlottery.state.gov), to see if you have won.