Burp Suite

http://portswigger.net/burp/download.html

Burp Suite is an integrated platform for attacking web applications. It contains all of the Burp tools with numerous interfaces between them designed to facilitate and speed up the process of attacking an application. All tools share the same robust framework for handling HTTP requests, persistence, authentication, upstream proxies, logging, alerting and extensibility.

Burp Suite allows you to combine manual and automated techniques to enumerate, analyse, scan, attack and exploit web applications. The various Burp tools work together effectively to share information and allow findings identified within one tool to form the basis of an attack using another.