A. Microsoft has a tool called 'Homer' (the developers obviously watch too much of The Simpsons!), which you can use to stress test all aspects of an IIS server.
"Microsoft Homer is a Web stress tool that is designed to realistically simulate multiple browsers requesting pages from a web application. It was developed by Web testers. The tool masks some of the complexities of Web server testing, which makes the tool desirable for anyone interested in gathering performance data about their Web site."
UPDATE: Since this FAQ was released, Microsoft has removed the Homer tool from its Web site. Although Homer is no longer available, Microsoft still offers a Web application testing tool, which you can download from http://www.microsoft.com/technet/treeview/default.asp?url=/technet/itsolutions/intranet/downloads/webstres.asp.