The Microsoft WAS web stress tool is designed to realistically simulate multiple browsers requesting pages from a web site. You can use this tool to gather performance and stability information about your web application. It simulates a large number of requests with a relatively small number of client machines. The goal is to create an environment that is as close to production as possible so that you can find and eliminate problems in the web application prior to deployment. You can script actions or record them by using your browser (then customize later by scripting). Simple interface, but very flexible in configuration and supports just about anything you need.
