If you've just built a new preview/beta SharePoint 2013 farm and followed this up with an installation of Visual Studio 2012 RTM you might be surprised to see that VS2012 doesn't include any of the SP2013 developer templates (just some updated versions of the 2010 ones which shipped in VS2010).

Long story short, you have to download these (probably because the timing between the two product releases didn't allow final versions of the SP2013 tools to ship in VS2012 RTM).

You have to download and install a (preview) version of the tools yourself from:

http://go.microsoft.com/fwlink/?LinkID=261869

You can read about other tools available for Office 2013 development at: http://msdn.microsoft.com/en-US/office/apps/fp123627