This is interesting for me also. I'm an Italian citizen and I would like to apply and relocate to the Bay Area. But I need to figure out the entire visa thing, and how to make it work for starting company.
Please look into the B category first (both b1 & B2), for the 3 months period. After YC, if you get funding, as a founder you should look at the E visa category. I believe E2 visa is the one for founders with secured funding that can realistically create 10 american jobs in the long run.