The founder of what had been one of the largest online poker websites agreed on Thursday to confront U.S. charges stemming from a long-running criminal case targeting internet firms like his operating illegally in the United States. Scott Tom, who founded Costa Rica-based Absolute Poker, pleaded not guilty in Manhattan federal court to charges he violated a federal internet gambling law and engaged in a money-laundering conspiracy. Tom, a citizen of Saint Kitts and Nevis who lived in Antigua, arrived in the United States voluntarily from Barbados on Thursday to face the charges, prosecutors said. He was released on a…