CamStudio - Free Screen Recording Software

CamStudio is "able to record all screen and audio activity on your computer and create industry-standard AVI video files and using its built-in SWF Producer can turn those AVIs into lean, mean, bandwidth-friendly Streaming Flash videos." To put it simply, this tool is perfect for screencasts. Set it to record and it makes a video of everything on your screen, great if you want to demonstrate software or get help with a error.