Another for the toolkit is ReelBean. Handy if your students are using their mobile phones to capture video. The .3gp files can be converted to other formats with this and converted back for moblie phones. The ReelBean website details:
ReelBean is a movie converter and player offering many features that are normally only available in expensive pro video applications. Most of ReelBean’s features are available for free.
ReelBean allows you to export your videos to many different video and audio formats, edit videos, extract sections of audio and video into separate files, and displays detailed video information and properties panels. It can be used to extract the audio from a movie and export it directly into iTunes. Individual frames or image sequences from movies can also be saved as image files.