This 12-hour animated trigonometry series includes a workbook and visualizations that could be useful as a pre-calculus learning/teaching tool.
I am the creator of EdPlayer, an ActionScript framework that I use in conjunction with the Flash Authoring Tool to animate math courses. More of my work can be found at www.math30.ca and www.math10.ca. After teaching, tutoring, and writing math for several years, it seemed like the next step was animating the things I was teaching. There were no clear post-secondary pathways to becoming a math animator, so I put together my own technology curriculum and used a combination of online videos and technical manuals to learn the required skills. In the last two years I have worked independently to produce over 35 hours of animated math tutorials aligned to the WNCP curriculum used in Canada. Hundreds of students use these animations every day to enhance their mathematics experience.
More info: http://www.math30.ca