Apple - How do I make iTunes video play slower or faster?

Right click on the file in iTunes and choose "Show in Finder." Then right click the file and open in Quicktime Player. In Quicktime Player you can choose the playback speed by using the A/V Controls (Command + K or Window>A/V Controls). From there, you can select the playback speed:

Alternatively, you could use VLC or another music player.

The Cmd+K shortcut no longer works in Lion or Mavericks.

Please see a post about increasing the playback speed in Quicktime.

The double arrow allows for integer increases in playback speed.

1. Right click on the iTunes playlist and click Show in Finder
2. Right click on the content in Finder and click Open with Quicktime player.
3. While watching the video/movie press Command and then right arrow or left arrow to increase or decrease playback speed, respectively.