As mentioned here: http://technet.microsoft.com/en-us/library/ee942200.aspx
The Office 2013 Proofing Tools Kit provides a single resource from which you can install any of the proofing tools.
You can install proofing tools on a local computer or deploy tools to a group of users. You can also customize and install the tools for one user or all users in your organization.
When will this be available for download, with previous versions of Office, this was usually available about 6 months after release