SmartSniff - SmartSniff is a packet sniffer that capture TCP/IP packets and display them as sequence of conversations between clients and servers.
Wireless Network Watcher - scans your wireless network and displays the list of all computers and devices that are currently connected to your network.
tcpdump - tcpdump is a common packet analyzer that runs under the command line.
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...
Packet Sender - Packet Sender can send and receive UDP, TCP, and SSL on the ports of your choosing.
My WIFI Router - Wifi Hotspot creator for Windows