Use Quicktime to watch Internet video, HD movie trailers, or personal media clips.
In Mac OS X Lion, Quicktime lets you record part of the screen, such as a specific window. It’s perfect for creating a video tutorial of an application. QuickTime can also trim the length of video clips or combine multiple clips into a single movie. Simply drag the clips you want into a movie window — QuickTime automatically scales or crops them so they match the dimensions of the movie.
Quicktime runs on both Mac and PC, and works with these popular video or audio formats: http://support.apple.com/kb/HT3775
