Free load testing tool for ASP.NET application?

Question

I've tried to test a rather complex ASP.NET app not under my control using my tried and true methods, like The Grinder, but it fails due to the authentication mechanism and the postbacks (very long URLs.)

Do you know of a good free tool that allows to stress test an ASP.NET application and hopefully allows for a replay of an actual session recorded via a provided proxy (something like Fiddler, or The Grinder itself)?

Any other suggestion (non free, manual methods) to make such a test are welcome as well.

Answer 1

Selenium Grid

Visual Studio Team System has a load runner also, not used it however and of course it is not free unless you already have it!