I just found out about a new project from TechSmith (of Camtasia fame) called the Jing Project, which combines a free screencasting (and still-image capture) application with an online hosting service.
The screencasts are recorded directly to flash, and the interface, while not very HIG-y, is pretty simple. Capturing isn’t as smooth as Screenflow, but hey, it’s free. It’ll be interesting to see where this goes.
Very slick!