Add Custom .NET Assemblies to the Add Reference Dialog
As you most likely know by now, the Add References dialog of Visual Studio .NET does not list each and every assembly on your machine, does not directly map to the Global Assembly Cache and does not list your custom assemblies. Typically this limitation is addressed by manually navigating to the *.dll of interest via the 'Browse' button.
However, if you wish to force VS.NET to display your custom assemblies within in the list maintained by the Add Reference dialog, all you need to do is place a copy of the assembly within the 'PublicAssemblies' folder located under C:\Program Files\Microsoft Visual Studio .NET 2003\Common7\IDE. Once you have done so, lo' and behold, your custom *.dlls are listed automatically.
Tip from Andrew Troelsen
Posted by: Duncan Mackenzie, MSDN
This post applies to Visual C# .NET 2002/2003