Create Shared Assembly And Use That Assembly In Web Application?

I just want to create Shared Assembly and use that assembly in our application.I am using VS 2005.

Step 1

I am trying to build a dll.

Create class library project <TestDllHell>.

Under that project add CalculationArea.cs file.

[Code]....

Then TestDllHell.dll add into GAC successfully.

Now I want to use it in my Website project so did the following steps but unable to view that dll in .Net Reference List Box.

•I go for Run regedit to edit the Windows Registry.

•Navigate to the HKEY_LOCAL_MACHINESOFTWAREMicrosoft.NETFrameworkAssemblyFolders key.

•Right click on the AssemblyFolders key, then select New > Key. Enter the name of your assembly (without the .dll extension).

•Double click on the key's (Default) value. The Edit String dialog will appear. Enter the full path of the folder where your assembly resides. Note that all assemblies in that folder will appear in the Visual Studio list.

•IMPORTANT! You must exit and restart Visual Studio to see your assembly in the Add Reference dialog.

My question is that

How can I get that dll in my add reference assembly List .Net section?

And if I modify that dll(TestDllHell.dll) then again register in GAC then version will be different,So how can I told my client application that which dll you choose?