Movie Masher: Free Open Source Online Video Editor:
"What is Movie Masher?
A set of Adobe Flash™ applets that provide front-end tools for common video editing tasks:
* Trim, composite and timeshift video
* Mix and fade multiple audio tracks
* Add effects, transitions and titling
An XML API is used to customize both the appearance and behavior of the tools:
* Colorize and reposition panels
* Reskin and bind interface controls
* Build preconfigured effects
* Integrate with CGI scripts"