US Taxes on Foreigner's Winnings

Hi, everyone. Must a foreign citizen (specifically, Polish) pay US taxes on gambling winnings, jackpots, etc.? What about taxes in Poland on US winnings? Is there a way to invest such winnings in a tax shelter; I know the standard deduction and exemption will shield roughly the first 10K of income. Or, does someone know a good source (book or lawyer) to figure out this stuff. Thanks for any leads.