Whenever I visit a cafe, library, or other public place with my laptop, I like to check my AirPort Status in my Mac's menu bar to see what wireless networks are available. But sometimes, if I find myself in a particularly busy place full of 'hotspots,' I would like to be able to view the list of networks sorted by signal strength.
Well, OS X allows you to do just that! First, though, you need to have the AirPort Status menu show up in your menu bar. This is done by going to the Network preferences in System Preferences. In the Network Status drop-down menu, select AirPort. Click on the AirPort tab, then at the bottom, click on the checkbox labeled 'Show AirPort status in menu bar' to enable it. A pie slice-looking icon will then show up in the menu bar.
When you want to see all the wireless networks available to you sorted by signal strength, simply hold down the Option key and click on the AirPort icon on the menu bar. The networks will then be sorted by signal strength, from strongest to weakest.
[robg adds: This definitely seems to work, and in both 10.3 and 10.4 (I tested both). I have two wireless networks visible from my home, and pressing the Option key puts the stronger signal at the top of the list.]
Mac OS X Hints
http://hints.macworld.com/article.php?story=20051125054859298