Visual Studio 2005 Web Deployment Projects
"Visual Studio 2005 Web Deployment Projects provide additional functionality to build and deploy Web sites and Web applications in ASP.NET 2.0 and Visual Studio 2005. This add-in includes a tool to merge the assemblies created during ASP.NET 2.0 pre-compilation, and provides a comprehensive UI within Visual Studio 2005 to manage build configurations, merging, and using pre-build and post-build tasks with MSBuild."
Read more and download from here
Basically this is an addin for VS2005 that lets you compile ASP.NET v2.0 applications using MSBuild. You can compile the whole site to one assembly for easy deployment, or you can compile each folder to it's own assembly, and so on. You can specify sections of the web.config file that should change from development to release, excellent for connectionString sections where you use a local database for development and another database when deployed on your ISP. There are more options too so it's worth reading the white papers.
Another article on compilation of ASP.NET v2.0 applications can be found here. It also covers the options available.