I routinely import legacy C++ projects then convert them to DLLs.  My working
IDE is Visual Studio 2005.

How do I recognize which projects are considered as .NET which projects are
considered managed/unmanaged?  My goal is to convert these projects to
managed .NET where it is painless, since this is our preferred platform.  I'm
assuming that I make this happen by initially adjusting the properties of the
project.

well the most obvious way is in the project properties...under Configuration
Settings / General / Common language runtime support (/clr)....if that's
turned on then it's managed.  You'll want to read up on the differences of
managed objects vs unmanaged objects tho

Fatal Execution Engine Error using unmanaged obj from 2 appdomains
Vista X64 GDI+ and System.Drawing errors
process exit event and thread synchronization
Ling to SQL and error recovery
In-Memory Assemblies