What is an ontology and how to develop one

These days my consulting work is taking me more and more into the area of Knowlege Modeling (see my blog from a few days ago). After my clients read that blog additional questions came up and two of the most prevalent were “what the heck is an ontology?” and “ok, so how do I develop an ontology?” I’ve been working on some materials for training and mentoring in the area of knowlege modeling myself but a couple of great resources are:

• Ontology Engineering PowerPoint presentation. That site is sometimes hard to reach so the PowerPoint is available here, too.
• Ontology Development 101 in PDF and HTML.