Wireless Network Watcher - scans your wireless network and displays the list of all computers and devices that are currently connected to your network.
Ping Meter Gadget - Customizable, graphical, semi-transparent ping (latency) meter.
WifiInfoView - Scans wireless networks in your area and displays extensive information, including: SSID, MAC Address, PHY Type (802.11g or 802.11n), RSSI, Signal Quality, Frequency, Channel Number, and more...
PingDoctor - PingDoctor is software that is considered to be the most powerful and easiest to use network route analyzer.
My WIFI Router - Wifi Hotspot creator for Windows
Fping (open source) - fping is a program to send ICMP echo probes to network hosts, similar to ping, but much better performing when pinging multiple hosts.