http://www.nikhilk.net/Project.WebDevHelper.aspx
Web Development Helper
A browser extension to provide tools for the Web developer including ASP.NET page and control developers.
ASP.NET Development Helper is a utility for ASP.NET page and control developers that plugs into Internet Explorer. It allows viewing information about the current page such as view state and trace, perform some operations on the server in the context of the running application to aid testing, and also allows monitoring requests and responses for diagnostic scenarios.
The tool requires beta 2 of the .NET framework v2.0. All features except the HTTP logs feature only work when the application is on http://localhost, in other words, it does not allow a remote user to interact with the server application.