Grasshopper[tm] is a handheld, wireless receiver designed specifically for sweeping and optimizing Local Area Networks. The instrument measures coverage of direct sequence CDMA networks which operate on the IEEE 802.11b standard allowing the user to measure and determine the AP (AccessPoint), PER (Packet Error Rate) and RSSI signal levels aiding in locating the hub and access points throughout a building. Grasshopper detects and differentiates from narrow-band multipath interferences such as microwave ovens and frequency hopping systems and features a built-in display, keypad and removable battery pack for true portability.
Category:   Software > Monitoring/Scanning

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

wavemon is a ncurses-based monitoring application for wireless network devices. It currently works under Linux with devices that are supported by the wireless extensions by Jean Tourrilhes (included in Kernel 2.4 and higher), e.g. the Lucent Orinoco cards.
Category:   Software > Monitoring/Scanning

KisMAC is an opensource and free stumbler/scanner application for Mac OS X. It has an advantage over MacStumbler/iStumbler/NetStumbler in that it uses monitor mode and passive scanning.
KisMAC supports several third party PCMCIA cards - Orinoco, PrismII, Cisco Aironet, Atheros and PrismGT. USB Prism2 is supported as well, and USB Ralink support is in development. All of the internal AirPort hardware is supported as well.
Please note: This program is not intended for novices, but for professional users. Take this as a warning
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