Let the hive mind of Engadget get that for you.
"As someone who doesn't reside in the USA, I was wondering what would be the best way to get internet for my computer in the US for a couple of weeks? If it were Europe I know I'd look for some prepaid data. Is there anything similar offered by American carriers? A MiFi or a data SIM that I can tether from would work, but I'm trying to maintain a tight budget. Help!"
wow, thats ridiculous. i just assumed that you can use phones underground, since ive never been on ny subway. when i was in s korea past 2 summers, people were watching live baseball games in the subway lines that were deep deep in the ground.