Current teaching strategies mainly follow instructional or constructive pedagogical models. In instructional model learning, contents are authored for teaching and evaluation of a concept. Whilst in constructive model, a student is exposed to the learning environment that allows him to learn new concepts, and his actions provide an evaluation of his understanding of the concept. Manual authoring of such learning contents not only requires specialized skills, thinking and dedication, but they also take large amount of time. Similarly within instructional environment, authoring any new content that supports the current teaching activity is very difficult. This paper presents an intelligent tutoring system (ITS) that facilitates the authoring of learning contents for both instructional and constructive teaching strategies. Proposed ITS uses semantic web formalism, namely ontology, for knowledge representation. This work shows that ontologies correctly and consistently models the domain knowledge that supports pedagogical activities, software development activities, ITS user friendly interface and provides robust reasoning facility for creation of dynamic contents. The proposed ITS provides authoring facility explicitly for teaching cognitive skills such as classification, relatedness, comparison (sequencing, discrimination, size etc.) and reasoning. With the use of ontologies, cognitive skills are translated into concepts/classes and properties/roles with restrictions. Reasoning and inference provided by ontologies are used for dynamic authoring of learning contents. Finally evaluation of proposed ITS is conducted for its correctness and consistency of domain knowledge, usability and efficiency & effectiveness of contents authoring.