There are several ways to deploy an assembly into the global assembly
cache:
1) Use an installer designed to work with the global assembly cache. This
is the preferred option for installing assemblies into the global assembly
cache
2) Use a developer tool called the Global Assembly Cache tool (Gacutil.exe)
provided by the .NET Framework SDK.
3) Use Windows Explorer to drag and drop assemblies into the cache.
4) use install shield. (注意：installshield里只有msi等几个类型的项目支持这个)
From:http://bytes.com/topic/net/answers/109942-deploy-assembly-gac