GAC (Global Assembly Cache)

Adding DLLs to the GAC (global assembly cache) is very similar to deploying any other files. The main difference is the Assembly-attribute, which can either be .net or win32.
The below examples show both versions.

.Net Assembly

Since .Net Framework 4, the .Net global assembly-cache is located at %windir%\Microsoft.NET\assembly, while previous versions used %windir%\assembly.
<Component Id="YourComponent" Win64="yes">
	<File 
		Id="YourAssemblyName.dll" 
		Assembly=".net"
		KeyPath="yes"  
		Source="$(var.YourProject.TargetPath)" />
</Component>
Win 32 Assembly

<Component Id="YourComponent" Win64="yes">
	<File 
		Id="YourAssemblyName.dll" 
		Assembly="win32" 
		KeyPath="yes" 
		Source="$(var.YourProject.TargetPath)" />
</Component>