kwavecontrol is a kde-monitoring tool for wireless devices showing diverse information like signal quality, bitrate, e.g.
Category:   Software > Monitoring/Scanning

AirCapture is a wireless packet monitor for the 802.11b Wi-Fi networks. AirCapture captures and decodes wireless network packets, which cannot be seen openly, and helps you visually monitor the WLAN activities. Using AirCapture, signal level and channel settings are monitored and it is capable of checking if the WEP key is properly secured. AirCapture is a member of PacScope, LAN analyzer family. OS: Windows 2000/XP
Category:   Software > Monitoring/Scanning

is another applett which shows how far away you are from the base-station.
Category:   Software > Monitoring/Scanning

InSSIDer is a free Wi-Fi network scanner for Windows Vista and windows XP. Because NetStumbler doesn't work well with Windows Vista and 64-bit Windows XP, we decided to build an open-source Wi-Fi network scanner designed for the current generation of Windows operating systems.
Category:   Software > Monitoring/Scanning

A library providing intuitive and easy to use routines for retrieving and manipulating data related to wireless interface devices.
Category:   Software > Monitoring/Scanning