I'd love to apply, but I'm on a H1-b visa and I'm basically in prison. How did the other international founders you worked with get around the immigration mess to start a company?
Find a great lawyer and have them use your startup Delaware corp as sponsor for your H1B. It's like moving employers. You may need to move $$$ into the company to demonstrate there is enough money to meet your minimum wage category and few other hoops. Alternatively apply for an investors visa but this will mean more capital injection into your US entity and more of those hoops to jump. Happy to talk offline. I'm no lawyer but have been through few Visas and similar scenario to yours. PS. There is no prison ;-)
As a Canadian, I'd suspect entering the US under a TN visa (Free trade agreement if you have an applicable university degree or 10 years experience) would probably do it. Anybody have experience with that when attending YC?
For TN you need a job offer. Specifically, when you try to enter the US on the TN status (it's not a visa technically), you'll be asked to show an offer letter from a US company that clearly states your intended role and salary.