>Keith,
>
>Thanks for the reply, and sorry I didn't acknowledge earlier.
>
>However, I am still developing the application module, including the COMMON project. i don't know if placing it in the Global Assembly cache will be possible, since I will need to make modification as the project progresses.
>
>Alfred

You don't have to place it into the GAC while it's still being developed. You can leave all of your current projects pointing to the local copy of the dll. Once everything is set, use a .NET deployment project to create a setup.msi that will install the common assembly into the GAC. Then run the deployment in your development environment once, and change the references in the other projects to point to the GAC instead of the local copy.

If you use a .NET deployment project to deploy the each application, you can tell each deployment project to install the common assembly into the GAC. Each deployment project will automatically handle any versioning issues.

This is the design pattern that MS envisioned when they created the GAC in .NET.