Rogue Amoeba has released Airfoil 4.7.5, which restricts searches to your local network to prevent possible issues with Back to My Mac and iCloud. The update also fixes an issue with failing to open a DVD in Airfoil Video Player, prevents a crash if the Transmit button gets pressed exactly as an output disappears, and provides some small improvements for Retina displays (a full Retina display update is yet to come). ($25 new with a 20-percent discount for TidBITS members, free update, 10.6 MB, release notes)
Option-Click AirPort Menu for Network Details
If you hold down the Option key while clicking the AirPort menu in Mac OS X 10.5 Leopard, you'll see not just the names of nearby Wi-Fi networks, but additional details about the selected network. Details include the MAC address of the network, the channel used by the base station, the signal strength (a negative number; the closer to zero it is, the stronger the signal), and the transmit rate in megabits per second showing actual network throughput. If you hover the cursor over the name of a network to which you're not connected, a little yellow pop-up shows the signal strength and type of encryption.