WEPCrack is an open source tool for breaking 802.11 WEP secret keys. This tool is is an implementation of the attack described by Fluhrer, Mantin, and Shamir in the paper "Weaknesses in the Key Scheduling Algoritm of RC4"
Some links to WepCrack information:
http://www.personaltelco.net/index.cgi/WepCrack
http://sourceforge.net/projects/wepcrack/
Also,
