“Coach’s Eye is an iOS5 app available through iTunes for £3 that can be used on the iPhone iPad and iPod. It allows you to add audio and visual feedback to new and imported videos. Particularly useful for sports and performing arts although it could be used with providing feedback on any visual practical process e.g. silversmithing techniques. For some good examples of the app in use watch the YouTube video
The swimming and karate kick examples are fairly good.”
Kevin Brunton, Going mobile, apps and devices (download docx) ADSHE.