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)
Adding Links in Snow Leopard's Mail
Apple Mail in Snow Leopard now has a Command-key shortcut for adding a link to an email.
If you use plain-text email, this will not be helpful at all, but if you send styled email, it's a nice shortcut for adding URLs to your email messages. Simply select the word(s) you want to make into a link, press Command-K, and enter the URL to build into the link.