The following list of free open source educational software comes from OpenDisc
Art and Graphics
GIMP – Edit digital photos and create graphics
GIMP animation – Create animations
Inkscape – Make professional looking vector graphics
Pencil – Animate your own cartoons
Blender – 3D graphic modeling, animation, rendering and playback
Tuxpaint – Drawing program for children ages 3 to 12
Multimedia
VLC – Play music, videos and DVDs
Audacity – Record, edit and mix music
TuxGuitar – Compose your own music
Piano Booster – Teach yourself the piano
Avidemux – Edit movies and add special effects
Infra Recorder – Burn your own CDs and DVDs
CamStudio – Record your actions on a computer
Really Slick Screensavers – Great looking screensavers
Science and Mathematics
Nasa Worldwind – Discover the earth and other planets~
Greenfoot – Teach yourself how to program
GraphCalc – A graphical calculator
Guido Van Robot – Learn how computer programs work
CarMetal – Cool mathematical modelling tool
Maxima – University standard computer algebra system
Celestia – Explore the universe in three dimensions
Stellarium – A planetarium on your PC
Games
FreeCiv – Control the world through diplomacy and conquest
FreeCol – Discover the ‘New World’ and build an empire
Numpty Physics – Solve puzzles using physics
TuxTyping 2 – Learn to type like a pro
Tux of Math Command – Test your mathematical skills
Winboard Chess – The classic game of chess
My addition to the above list:
Openoffice – word processing, spreadsheet, “PowerPoint like” presentation, drawing, database program
My book, Formative Assessment: Responding to Your Students, is available through Eye on Education.
Also, my book, Successful Student Writing Through Formative Assessment, is available through Eye on Education.
Education with Technology Harry G. Tuttle 
