Tim Hortons (NYSE:THI) President and CEO Don Schroeder has resigned, effective immediately, the company reported today.Paul House, the Corporation’s Executive Chairman and former President and CEO, has been appointed to also serve as Interim CEO until the Board completes its succession planning process and appoints a new CEO.Interim CEO Paul House said in a release, "Don Schroeder has made significant contributions to Tim Hortons during his 20 years of service, and although a transitional arrangement could not be reached, we appreciate his leadership as president and CEO since his appointment in 2008." House added, "We have a talented, experienced and highly capable executive group, and we will continue to drive execution of our established strategic growth plans and initiatives, which are designed to capitalize on market opportunities, as the Board concludes the process to appoint a new CEO."