I'm from the Philippines and will have a project assignment in Montreal for 3 years. Can I apply for US visa there? how? I'd like to cross to NYC for a few days tour.
Assuming you have a long term visa or a permanent residence status in Canada, you can apply for a visitor visa from Montreal at the US consulate general. A friend of mine who lived here on a work visa was able to apply for a visitor visa a few years ago.
The State Department's website doesn't mention any requirement where you can apply, other than your place of permanent residence.
You must schedule an appointment for your visa interview, generally, at the U.S. Embassy or Consulate in the country where you live. You may schedule your interview at any U.S. Embassy or Consulate, but be aware that it may be difficult to qualify for a visa outside of your place of permanent residence.
The rest of the application is the same formality anywhere and you can do most of it online. You can see all their requirements here