- Screenflow is a bit tricky to wrap your mind around, but a powerful, useful tool once you do. I particularly like their ability to hide your desktop temporarily while making a screencast, and you can export it into a number of formats. The big downside is the cost: 99 USD isn't all that steep, but when you're just going to make a handful of screencasts, it's a bit much to justify. Still, the most powerful of the ones I've seen so far.
- iShowU is a techy little program that supports a ton of output formats and sizes. At 20 USD, it's a whole lot cheaper than Screenflow too. On the downside, it doesn't seem to have video-editing built in, and - since it records in a box of a particular size around the mouse - the resulting video is kinda jumpy. But if you're looking for a whole-screen recorder, this might be just what you're looking for. Thanks, Curren, for recommending this program to me.
- Screenr has a very cute interface, and is completely on-web and cross-platform. I love the simplicity of this. I don't think I can get the movie out of this, though, which might be important for making these videos. You can't beat the price, though: free.
- Jing - I haven't had a chance to try this yet, but it looks interesting.
I'll update this list as I spot other tools. Do you have a preferred screencasting software for the Mac? Please let me know!