Some countries are exempted from American visas, consult the section "Visa Waiver Program (VWP)" to know the countries and the requirements. To get your visa, you must take an appointment with the United States Embassy Consular Services Canada in Montréal.
The Visa Waiver Program (VWP) allows foreign nationals from certain countries to be admitted to the U.S. under limited conditions and for a limited time without obtaining a visa. To find out which countries that are exempted and what are the requirements, consult the website of the United States Embassy Consular Services Canada in Montréal.
Upon arrival at the border, you will have to present a printed form and pay some fees.
As always when visiting another country, you must first verify that your health insurance will cover you. For those registered with the RAMQ, this Quebec insurance only covers you within the province. Remember that Medical care in the States could cost you thousands of dollars so you must make sure that you have a medical or travel insurance before you cross the border.