Technitium MAC Address Changer - Technitium MAC Address Changer (TMAC) is a freeware utility to instantly change or spoof MAC Address of any network card (NIC).
NetSpot - NetSpot is a free app for wireless site surveys, Wi-Fi analysis, and troubleshooting
Axence netTools - Axence netTools is completely free of charge, both for home and commercial use – all you have to do is to register. A tool for professionals – and others.
Vistumbler - Vistumbler is a wireless network scanner for Windows Vista and Windows 7. Features:
Zabbix - Track, record, alert and visualize performance and availability of IT resources
Wifi Analyzer - Wifi Analyzer is a handy tool which helps you to select a better channel for your wireless router.