There are a lot of different tools for filming, which of course are generally divided by operating system.
Video-capturing:
Win: Fraps, Camstudio, Hypercam, Xfire, WeGame and others
Mac: Berio, Camtasia, and others
Editing:
Win: Sony Vegas, Adobe Premiere, WinMovieMaker, Corel VideoStudio, VideoSpin, many others
Mac: iMovie, Adobe Premiere, Final Cut Pro, many others.
Linux: Kdenlive (http://kdenlive.org)
Peripherals:
SpaceNavigator 3D Mouse