As of March 20th, 2010, and at the request of the U.S. Department of Homeland Security and the Customs and Immigration authority, citizens of countries included in the U.S. visa waiver programme* travelling to or through the United States must obtain permits under the ESTA (Electronic System for Travel Authorization).

How to Obtain the Authorisation
The travel permit can be obtained only via the U.S. Department of Homeland Security web site, https://esta.cbp.dhs.gov, where a form must be filled out. It is available in Spanish and 20 other languages. It must be submitted at least 72 before the start of your trip.

In most instances permission to visit the United States will be granted in a few seconds, although the procedure may take as long as 72 hours.

When the authorisation is obtained it should be printed and kept along with your passport. If the request is denied, you should contact the nearest United States Embassy to find out if a visa may be issued.

Validity
The ESTA permit will remain valid for two years and may be used for multiple entries to the United States. If in this period there are changes in the passenger’s home address or travel destination, he or she may visit the same web site to modify the data accordingly. When a new passport is issued, the holder must request a new ESTA permit.

The new rules do not exempt passengers from the obligation to supply data under the Advanced Passenger Information System (APIS), to possess a machine-readable passport, or to fill out landing cards on board aircraft.

* Countries included in U.S. Via Waiver Programme:

Andora	France	Luxemburg	Slovenia
Australia	Germany	Monaco	Spain
Austria	Iceland	New Zealand	Sweden
Belgium	Ireland	Norway	Switzerland
Brune	iItaly	Portugal	The Netherlands
Denmark	Japan	San Marino	United Kingdom
Finland	Liechtenstein	Singapore