The aircrack suite is an excellent collection of tools written by Christophe Devine to perform packet capture, packet cracking and WEP/WPA cracking.
AiroPeek NX v2.02
Best wireless protocol analyzer and security. Wildpackets' AiroPeek NX is a software that performs packet analysis of IEEE 802.11 wireless LANs in support of security audits, site surveys, network management, and troubleshooting.
AirSnort is a wireless LAN (WLAN) tool which recovers encryption keys. AirSnort operates by passively monitoring transmissions, computing the encryption key when enough packets have been gathered.
NetStumbler is a tool for Windows that allows you to detect Wireless Local Area Networks (WLANs) using 802.11b, 802.11a and 802.11g.
It has many uses:
• Verify that your network is set up the way you intended.
• Find locations with poor coverage in your WLAN.
• Detect other networks that may be causing interference on your network.
• Detect unauthorized "rogue" access points in your workplace.
• Help aim directional antennas for long-haul WLAN links.
• Use it recreationally for WarDriving.
*Wifi Drivers (Must Install)