Ask HN: Do American startups hire developers from foreign countries?

Hi, I am from Brazil, but I did travel a lot as tourist and know a few countries, but I miss some work experience outside, and Brazil is a little behind in the startup business my focus right now. I would like to work in the US for a startup for a while( like 2 years, don't wanna live there, just some exp. ) to get some extra knowledge, I think I already have the resume for it, Java and learning some Rails. But I can't see how... Because I can only get a work visa as if I find a Job, but Jobs only take resumes from people with working visas. so... the old egg and chicken thing. What do you think are good resources ( monster ? linkedln ? ) to find a in a startup job there ? and What are the upsides and downsides of working in IT in the US ? Thank you !