inSSIDer - inSSIDer Essential makes it easy to maintain small business WiFi.
TCP Optimizer - SpeedGuide.net - The Broadband Guide. Cable modems, DSL, Wireless, Network security. Free speed tweaks and TCP/IP tools for optimizing system performance.
NetSpot - NetSpot is a free app for wireless site surveys, Wi-Fi analysis, and troubleshooting
Throttled Pro - Throttled Pro optimizes your internet connection and provides QoS (Quality of Service) to Mac OS X.
Vistumbler - Vistumbler is a wireless network scanner for Windows Vista and Windows 7. Features:
SpeedConnect Internet Accelerator - SpeedConnect Internet Accelerator is software for optimizing your internet connection and boost the speed as well as response.