Broncos coach Mike Shanahan has signed a three-year contract extension, keeping him in Denver through the 2011 season. Shanahan, 54, led Denver to Super Bowl victories in 1997 and 1998. Since becoming head coach in January 1995, he has led the Broncos to seven playoff appearances and a 123-69 regular season record, best in the NFL over that span. Although he's had just one losing season, in 1999, following John Elway's retirement, Shanahan has just one playoff win in the last eight seasons. Team owner Pat Bowlen announced the extension Monday in a news release.