I can get easily see what projects and dlls a single project references from within a Visual Studio .NET project.
Is there any application or use of reflection that
Structure101 can do that. You can browse a model by assembly and/or namespace, and clicking on any dependency at any level give you all the code-level references that cause the dependency. The .NET version is in beta, but it's been available for other languages for years, so it's very mature. Here's an example screen shot. alt text http://www.headwaysoftware.com/images/assemblies.jpg