Camtasia Studio. http://www.techsmith.com/camtasia.html
Comment: From the makers of Jing. I liked my experience with Jing and I would like to explore a tool with more capabilities.
Adobe Presenter: http://www.adobe.com/products/presenter.html
Comment: I liked the example produced in class. Many students are familiar with PDFs and the Adobe Reader, so working with this format should not be difficult.
Comment: I have not tried wikis in a classroom, but this would be a great tool for promoting constructivist pedagogy.