A fully automated, active web application security reconnaissance tool. Key features:
High speed: pure C code, highly optimized HTTP handling, minimal CPU footprint - easily achieving 2000 requests per second with responsive targets.
Ease of use: heuristics to support a variety of quirky web frameworks and mixed-technology sites, with automatic learning capabilities, on-the-fly wordlist creation, and form autocompletion.
Cutting-edge security logic: high quality, low false positive, differential security checks, capable of spotting a range of subtle flaws, including blind injection vectors.

Download:
http://code.google.com/p/skipfish/downloads/list