A number of people wrote to tell me that John Norstad has released NewsWatcher 2.0b3 shortly after TidBITS-233 came out, mentioning 2.0b2. The Internet moves quickly, and something in one issue may be out-of-date by the next (although I'm usually correct as of the day the issue is dated, since I check URLs during editing). You can get NewsWatcher 2.0b3 (and subsequent versions in the same directory) at:
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.