Jing Project: Visual conversation starts here. Mac or Windows.
I can’t remember where I learned about Jing but it’s really a great tool. It allows you to grab images and or video from your desktop and send them to flickr or Screencast or to an FTP server. You can then share the files you have created out via link or embed. For example you could use Jing to record your actions on the desktop in order to make an instructional video for someone, upload it and then send them the link to watch. It’s also great for grabbing images from the web or PDF files or anything that you just want to grab a small piece of. I used it to grab the Jing logo from their website. It’s available for Mac and Windows and I use it on both. It’s made by TechSmith who are also the makers of Camtasia Studio. It’s also free!