http://msdn.microsoft.com/library/default.asp?url=/library/en-us/dndotnet/html/win32map.asp
This article identifies the Microsoft .NET Framework version 1.0 or 1.1 APIs that provide similar functionality to Microsoft Win32 functions. One or more relevant .NET Framework APIs are shown for each Win32 function listed. The intended audience for this article is experienced Win32 developers who are creating applications or libraries based on the Microsoft .NET Framework, but anyone looking for a managed counterpart for a Win32 function could find this document useful. (85 printed pages)
Very cool, now just give me the API Viewer from VB6 updated to .NET, and I'd be set.