There is a post on IIS.net titled "Using Visual Studio 2008 with IIS 7.0", but I don't quite believe that's what people do. (Among other gems, it suggests publishing your web app after every change.)
If you debug your ASP.NET applications in IIS7 instead of Cassini, I would love to hear your methods, tips, and tricks.
Edit: I'm referring specifically to local debugging.
I simply attach Visual Studio to the IIS worker process, if you have multiple app pools then you can run "issapp" to get the appropriate PID.
I never debug by clicking "Start Debugging".
This has a nice advantage of working on remote servers as well, if you have installed msvcmon.