LiveStage Pro is one of the best tools that I have used. It works very well if you want to build the interactive video with QuickTime format and don’t like hand coding with the QScript. You can probably get most of things done by using this cool authoring tool.
[ QuickTime ]
References:
QuickTime Fundamentals
Interactive Movies
Resources Page
Developer Page
Authouring Tools list
Another List
Software:
Live Stage Pro - QuickTime Interactive Authoring Tool
Blue Abuse (not available)
BackStage - Live Stage references