Former Pennsylvania Sen. Rick Santorum plunged into the 2012 Republican presidential sweepstakes Monday, saying he wants to protect American freedoms under threat from President Barack Obama. Once the No. 3 Republican in the ranks of the Senate GOP leadership, Santorum said, “I’m ready to lead. I’m ready to do what has to be done for the next generation, with the courage to fight for freedom, with the courage to fight for America.” He spoke on the steps of a county courthouse in Somerset, Pa. … Two bidders have already driven up the price of a private lunch with billionaire Warren Buffett to over $1.5 million, and the online charity auction runs all week. The Glide Foundation uses the proceeds to help provide social services to the poor and homeless in San Francisco. Last year’s $2.6 million winning bid set a record for the most expensive charity item eBay ever sold. The winners usually dine with Buffett for several hours at New York’s Smith and Wollensky steak house. … Katie Couric — thanks in part to Oprah Winfrey — will try out a daytime talk show. Winfrey’s exit from the market she dominated for much of the last two decades is providing Couric with an opening. The former “CBS Evening News” anchor and “Today” show host and ABC set September 2012 for the premiere of Couric’s new show. Couric will have a part ownership stake in her new talk show, which reunites her with Jeff Zucker. The former NBC Universal chief, who was in the control room during many of Couric’s years at the “Today” show, will be executive producer of the talk show. Scott Pelley took over as the new “CBS Evening News” anchor on Monday.