tax question: what about WSOP winnings from germans?

[jjacky]

hi,

not that i won yet, but i booked a trip.

when i was in vegas the last time, me was told by a poker room employee, that 30% of my winnings are subjekt of withhold. but that i would be able to get 100% of it back (because gambling winnnings are tax free in germany).
unfortunately i am not positive that this information is correct.

so my questions are:
1. do i have to pay taxes in the US in case i am winning. if so, how much?
2. are my winnings subject of withhold. if so: how much and how do i get it back?