QoS-based service selection mechanisms will play an essential role in service-oriented architectures, as e-Business applications want to use services that most accurately meet their requirements. Standard approaches in this field typically are based on the prediction of services' performance from the quality advertised by providers as well as from feedbacks of users on the actual levels of QoS delivered to them. The key issue in this setting is to detect and deal with false ratings by dishonest providers and users, which has only received limited attention so far. In this paper, we present a new QoS-based semantic web service selection and ranking approach with the application of a trust and reputation management method to address this problem. We will give a formal description of our approach and validate it with experiments which demonstrate that our solution yields high-quality results under various realistic cheating behaviors.