Rogue Amoeba has released Airfoil 4.5.7, a minor update to its popular network audio streaming app for the Mac. Most notably, the new version adds support for Mac OS X 10.7 Lion to the Instant On component, which helps capture both system audio and audio from already-active applications. It also fixes several bugs and memory leaks, including one that prevented AppleScript scripts using the System Audio device from working. ($25 new, free update, 11.4 MB, release notes)
Two Shortcuts for App Exposé
If you want to see all the windows for a particular app via App Exposé, there are two hidden shortcuts. For either, start by pressing Command-Tab to bring up the app switcher. Then, while still holding down the Command key, press either the 1 key or the up arrow. That puts you into App Expose mode, with all of an app's windows showing, and recent documents in a row across the bottom of the screen. Let up on the Command key, and then you can press Tab to cycle through all the running apps.