We've mentioned a few screen capture and screencasting apps here recently, but interest in finding new and shiny tools for the job still seems high. There are a couple of possibilities on the porting and development front that might excite the screencast community:
First, Jing Project developer TechSmith - long a dominant vendor for Windows screencasting tools - has indicated that further Mac development is in the cards: the Mac plans page says "...we are actively pursuing a Mac version of Camtasia Studio" and evaluating a release of SnagIt for the Mac. I've used Camtasia on the Windows side and I like it, which makes me optimistic for the Mac version's future. You can sign up for email updates at the TechSmith Mac page, or follow the feature request link if there's something you can't live without.
On the other side of the fence is Adobe's Captivate 3, a high-end screencasting and presentation tool for Windows that's aimed at instructional designers and training applications. While it's pricey, casual users can leverage it to create podcasts or 'casual learning' environments quickly and easily. There isn't an official roadmap for Captivate development on the Mac yet, but Adobe representatives were clear in a recent conference call on the product: if you want to see Captivate come to the Mac, let Adobe know via the company's feature request form.