Coursera is a website that has many free courses from different sources, including a number of universities. One course, on horse care, has a video detailing some of the finer points of horse evolution. This video discusses Eohippus and other early horses, so it is a good starting point for any day with a number of videos on early horses. Aside from this, Eohippus is not much of a screen start. The small horses did have one "starring" role in the 1969 movie Valley of Gwangi. Built by Ray Harryhausen, the small model horses were far smaller than they would have been in real life, but they are still adorably stop-motion animated in great detail.