Using integrated authentication with a 2003 Web Server

Windows 2003 Application Server IIS 6.0 C# & .NET v1.1 I'm having difficulty with the integrated authentication peice of IIS when attempting to run a web app from my local machine. When attempting to run the application with IE, I'm prompted for a username/login. If I supply the Admin login for the server, then I'm granted access. Obviously I'd like the users' windows login to be used instead. I believe I've set the proper security settings for the folders on the app server but that could be an issue. Another issue could be the Intranet Zone setting within IE... Any ideas as to why I'm forced to login to the Web Server when trying to access a web app? Thanks