WASHINGTON -- Wal-Mart has signed a contract to help power hundreds of its stores using wind energy, one of the largest investments in the field by a U.S. retailer.

The four-year agreement with Duke Energy is expected to provide up to 226 million kilowatt-hours of power each year to about 360 stores and distribution centers in Texas, about 15 percent of the total electricity used. The company said the purchase will result in the reduction of about 139,000 metric tons of carbon dioxide, the equivalent of what 25,000 cars would emit.

The move is the latest step in the company's three-year-old effort to transform itself into a more sustainable business. Wal-Mart chief executive Lee Scott has vowed that the retailer will eventually be completely supplied by renewable energy. The deal with Duke is expected to be announced today.

Wal-Mart declined to disclose the amount of the contract, but a spokeswoman said the company would not pay more for renewable energy than it does for traditional energy sources.

LOS ANGELES -- A group of college students who lit a ridge-top bonfire is being blamed for accidentally sparking one of three ferocious wildfires that collectively destroyed about 1,000 homes and blacked more than 65 square miles.

An anonymous tipster told police 10 students gathered a week ago near an abandoned home in the hills of Montecito, Santa Barbara County Sheriff Bill Brown said Tuesday.

The students, aged between 18 and 22, apparently believed they had put out the fire before leaving. Fire officials said it is not uncommon for such fires to have the potential to re-ignite days later.

NEW YORK -- The prostitute at the center of the scandal that brought down former New York Gov. Eliot Spitzer has apologized to his wife.

Ashley Alexandra Dupre tells People magazine that the FBI informed her in early March that it was investigating one of her clients. A few days later, she found out which client when she recognized Mr. Spitzer on TV -- resigning.

Her message to the former governor's wife, Silda Wall Spitzer: "I'm sorry for your pain."

SAN FRANCISCO -- The California Supreme Court agreed yesterday to review legal challenges to Proposition 8, the voter initiative that restored a ban on same-sex marriage but refused to permit gay marriages to resume pending a ruling.

Meeting in closed session, the state court asked litigants on both sides for more written arguments and scheduled a hearing for March. The court also signaled its intention to decide the fate of existing same-sex marriages.

Yesterday's decision to review the lawsuits against Proposition 8 did not reveal how the court was leaning. The court could have dismissed the suits, but both opponents and supporters of Proposition 8 sought review to settle legal questions.