We don't do too many screencasts here on Webware. But when we do, my personal favorite is Telestream's Screenflow. It's a nice app, but it's Mac-only which means I can't use it when I'm on my office PC. In keeping with the mission statement of this blog, worth a look is software-free alternative Screencastle. This Java-based tool will record a select region of your screen and any audio from your computer's microphone. It then hosts it for you, complete with download links so you or your users can download a local copy for offline viewing.
Sure, it doesn't have all the bells and whistles of a standalone screencasting application such as editing, adding on-screen text, or being able to scale the video to highlight details. But if you want to create a how-to video for a friend or family member this is hands-down one of the easiest solutions out there. Just look at this video I made in less than a minute:
Screencastle is a consumer-friendly demo of Skoffer, an open service for adding software-free screen recording to Web apps or support sites to make it easier for people to create how-to's or document problems. There's even a WordPress plug-in which puts a small recording button in the compose window so you can record something on the screen to drop into your post.
See also: Screencast-O-Matic