Ontology is a fundamental data object for organizing knowledge in a structured way in many areas ranging from philosophy to Knowledge Management. Knowledge capture, knowledge integration and knowledge delivery are the essential parts of dynamic knowledge management. E-Learning is considered to be an integral part of knowledge delivery system. Information architect plays an important role in developing the system, and are primarily responsible for capturing and modeling knowledge from various Information sources as a part of eLearning. Ontology is found to be useful and efficient as a basis to capture the knowledge, model it in a structured way and disseminate it for further processing from various information sources. In this paper, we present a brief description on the role of ontology in e-learning and review the ontology building tools. The purpose for reviewing ontology building tools is to determine the toolkit most suitable for ontology creation, editing, and mind/concept mapping from the view points of Information Architects (IAs) who play a significant role in designing knowledge management systems. The paper also gives a fundamental understanding of ontology tools available on the market as open source products as well as commercial products in terms of their capability, availability, enhancement and further development. We provide a ranked list of the tools based on our needs and suitability for the IAs.
[Due the large number of images and amounts of code in this article, it is available as a PDF only.]