We heard a lot of feedback about the build process and new project system for managing more complex sites, build strategies, and deployment. As a result, we've been working on a add-in for Visual Studio 2005 that enhances the built in support for MSBuild and the general Web build model. The code is in Beta, but you can begin using it immediately.
Check out the main page at: http://msdn.microsoft.com/asp.net/reference/infrastructure/wdp/default.aspx
UPDATE: Great walkthrough from ScottGu here
From the site:
Visual Studio 2005 Web Deployment Projects provide additional functionality for building and deploying Web site applications that you create in ASP.NET 2.0 and Visual Studio 2005. This add-in includes a new tool that enables you to merge the assemblies created during ASP.NET 2.0 precompilation, and it provides a comprehensive UI within Visual Studio 2005 for managing build configurations, merging, and pre-build and post-build task using MSBuild.