Because we're also big fans of easy, we have newfound appreciation for Capture Fox, which adds screencasting capabilities to the Firefox browser. No additional software required, no service to sign up for.
I could drone on about it for a bit, but you can learn what you need to from the developer's informative video:
Thankfully, you're not limited to recording whatever's in the confines of the browser itself -- Capture Fox can capture anything displayed on your screen, complete with audio (assuming you have a microphone, of course).
Just one letdown: When you're done recording, you're left with an AVI file. That's fine -- you can manually upload it to YouTube, e-mail it to others, or whatever -- but we're partial to screencasting solutions that include automatic uploading and/or hosting.
With that in mind, check out these other options: