About 4 million U.S. homeowners are 90 days or more delinquent on their loans or in foreclosure proceedings, Moody's Economy.com says. A federal loan modification program is helping a relative few. Experts fear that a new wave of foreclosures will hit this year as prolonged unemployment makes it difficult for millions of homeowners to pay their mortgages -- and many of them aren't likely to get much help from a federal program aimed at keeping them in their houses.