Today Microsoft have silently released the first Service Pack for all Microsoft Office 2013 products.These include the Office 2013 product suite as well as Exchange Server 2013, SharePoint Server 2013, SharePoint Foundation 2013.
See below for the download Links.
Note: I was unable to find any direct download links to Visio or Lync Server 2013 as of yet.
Office 2013 SP1 32-bit
Office 2013 SP1 64-bit
Exchange Server 2013 SP1
SharePoint Server 2013 SP1
SharePoint Foundation 2013 SP1
Have fun! 🙂