The best screencasting software is Screenflow. It also is $100 so it’s not the cheapest out there but it is the best. It is so easy to use. I’ve used Jing, the 5 minute time limit sucks (it’s the free version) and the fact that it’s build in Flash sucks too. Screenflow blows Jing away. It always easily uploads to Youtube.
Here are tips on how to zoom, pan and show keystrokes.