Used to be your could run regsvr32 and have a dll show up across your system and, to the point today, in the VB6 IDE.

As I discovered today, and as this blog describes in some detail, it's a bit more difficult nowadays.

6.) Now even after doing all this and having your assembly in GAC you shall not be able to see it when you try to open add referenes... For that there is another trick... See the point is Add Reference is a IDE specific stuff and so you need to alter those setting... for that reason you need to create certain keys in the Registry
7.)To display your assembly in the Add Reference dialog box, you can add a registry key, such as the following, which points to the location of the assembly
[HKEY_CURRENT_USER\SOFTWARE\Microsoft\.NETFramework\AssemblyFolders\Debug]@= 'C:\\MyProjects\\ClassLibrary1\\Bin\\Debug\\' where Debug is nothing but the name of the folder in which the assemblies resides. You will not file any enteries here in case you have never tempered this area... so create this whole structure in the registry...