iStumbler is an easy way to scan for information about the Wi-Fi environment around you, as well as see available Bluetooth devices, and what Bonjour services are available on the local network. The latest version, release 99, works only with Mac OS X 10.6.2 or later, adds support for the 5 GHz band used by 802.11a and 802.11n, and takes advantage of the coordinate-based location feature in Snow Leopard to allow GPS-like tracking as the application scans. (Free, donation requested, 1.1 MB)
Springy Dock Tricks
If you drag a file and hover over Dock icons, various useful things happen which are similar to Finder springing. If it's a window, the window un-minimizes from the Dock. If it's a stack, the corresponding folder in the Finder opens. If it's the Finder, it brings the Finder to the foreground and opens a window if one doesn't exist already. But the coolest (and most hidden) springing trick is if you hover over an application and press the Space bar, the application comes to the foreground. This is great for things like grabbing a file from somewhere to drop into a Mail composition window that's otherwise hidden. Grab the file you want, hover over the Mail icon, press the Space bar, and Mail comes to the front for you to drop the file into the compose window. Be sure that Spring-Loaded Folders and Windows is enabled in the Finder Preferences window.
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