Steve Ballmer announced Office 2013 few hours ago. During his presentation, Office 2013 Preview was released for a download. SharePoint 2013 Preview and documentation just got uploaded as well.

Here are few useful links:

• SharePoint 2013, Exchange 2013, Lync 2013, Office Web Apps Server, Project 2013, Visio 2013 and Office Professional Plus 2013:
  http://www.microsoft.com/office/preview/en/try-more-products

• Office 2013 and SharePoint 2013 developer training:
  http://msdn.microsoft.com/en-US/office/apps/fp123626

• SharePoint 2013 ITPro training:
  http://technet.microsoft.com/en-us/sharepoint/fp123606

• Press release:
  http://www.microsoft.com/en-us/news/Press/2012/Jul12/07-16OfficePR.aspx

• Office Customer preview:
  http://www.microsoft.com/office/preview/en

• Apps for SharePoint 2013:
  http://officepreview.microsoft.com/en-us/store/apps-for-sharepoint-FX102804987.aspx

• Build apps for Office and SharePoint (jump start and code samples):
  http://msdn.microsoft.com/en-US/office/apps

• Office for IT pros:
  http://technet.microsoft.com/en-US/office

• Microsoft SQL Server 2012 Service Pack 1 CTP3 (brings Office 2013 and SharePoint 2013 BI compatibility):
  http://www.microsoft.com/en-us/download/details.aspx?id=30375