Wikipedia
Weplab
Weplab is a tool designed to teach how the Wired Equivalent Privacy (WEP) wireless encryption protocol works, explain the security vulnerabilities in the protocol, and demonstrate attacks that can be used to compromise a WEP protected wireless network. Weplab is designed not only to crack WEP keys but to analyze the wireless security of a network from an educational point of view. The author has attempted to make the source code as clear as possible, instead of implementing optimizations that would obfuscate it.
Weplab works on Unix-like systems like GNU/ Linux, * BSD or Mac OS X and with Cygwin layer on Windows.