Desktop directors will appreciate many of ScreenFlow 2.0's new features. You can add new 2D and 3D video transitions between clips simply by pushing two clips together. The ability to tweak the speed of video clips--and, in particular, to add freeze frames--should make it much easier to get your audio to line up just right, instead of necessitating time-sucking virtual reshoots. And capturing no longer requires Steadicam-caliber patience; you can pause and resume the recording process any number of times, and create just a single clip timeline.

Unless you're making a screencast about your new Charlie Chaplin software, you probably care about audio, too. ScreenFlow 2.0's live audio scrubbing and ability to detach audio for more advanced cutting and pasting make sound manipulation more powerful. And the new audio-ducking feature automatically adjusts the volume of your background music whenever your voiceover comes in.

Other new features include built-in YouTube export; hue, saturation, and brightness controls; keyboard shortcuts; and a slew of other performance tweaks, all optimized for Snow Leopard.

ScreenFlow 2.0 costs $99. Registered owners of the original ScreenFlow can .

We'll have a lot more to say about ScreenFlow 2.0 in our upcoming review.