Jing is a new screencasting application in beta for creating snapshots and video captures of your computer screen.
The creators of Jing want you to think about it as a tool that can help you explain and share with buddies what you see and do on your computer. With Jing you can select "an area of your screen, capture it as an image or record it as a video, and then click share. "
You can also draw over the captured picture or record your voice over the video to better explain to your friends your screencast. A microphone hooked to your PC is needed to record your voice. After you finish Jing will create a web address with your video or image and you can send to your friends.
Another free presentation software program for creating screencasts is Wink. "Using Wink you can capture screenshots, add explanations boxes, buttons, titles etc and generate a highly effective tutorial for your users."
If you are curious how Wink tutorials look like, pick one from the link below:
To work with Wink you need to have Macromedia Flash Player installed on your computer.