Hooks are scripts that you can use to run additional code when running Git commands. They are not stored in the repository so need to be set up on each computer individually.
You can create templates for your hooks that will be used whenever you create a new repository. To do this, put your scripts into the template folders on your local machine.
Program Files (x86)\Git\share\git-core\templates
When you next run git init you will then have these templates installed by default. Additionally, you can run git init in existing repositories to update the templates (it will not do any damage to the repo itself).