Good, free video-editing software?

http://sourceforge.net/projects/jahshakafx/

http://avidemux.sourceforge.net/

For the average person, the best video editors available are iMovie for Macs, and Windows Live Movie Maker for Windows Vista/7 (or the older Windows Movie Maker for XP). Both are free, and have a drag-and-drop interface for working with multiple clips. iMovie is quite a bit better than Windows Live Movie Maker, if for no other reason than that Windows Live Movie Maker is extremely limited in the video formats it can produce (and actually can only export wmv videos, though there are plugins available to upload videos directly to YouTube and other web sites). But both are quite sufficient for most amateur video editing projects.

Avidumux is a free, cross-platform video editor that is excellent for editing individual clips, but less so for working with multiple clips as it lacks a drag-and-drop interface or the ability to add transitions between clips. However, it's one of the best general-purpose video transcoders available, as it makes it quite simple to convert videos of many different formats into a wide variety of other formats. If you use Windows Live Movie Maker to edit your video clips together, you can then use Avidemux to clean it up and convert it to the desired format.

Windows Live Movie Maker.