If you're looking for a graphical configuration tool that doesn't expose the XML, you're going to be somewhat limited.
IIS Manager has limited support for editing configuration files for ASP.NET 2.0 sites. Additionally, if you are using Enterprise Library in the web app, there is (or was, last time I used it) an Enterprise Library Configuration tool which shipped with it, and allowed some GUI-based editing of the Enterprise Library-specific sections.
Otherwise you're pretty much in a mode of using your favorite text editor. If you don't feel like the weight of Visual Studio, I'm a big fan of ConTEXT.