The Office team has created lots of great training content to help users learn about the new features in Office Customer Preview and Office 365.
Content
URL
Self-paced Office training
http://officepreview.microsoft.com/en-us/support/training-FX101782702.aspx
What's new with Office training video
http://officepreview.microsoft.com/en-us/support/redir/va102840846.aspx
Getting started resources
http://office.microsoft.com/en-us/support/getting-started-with-office-2013-FX102809998.aspx
What's new in Microsoft Office
http://officepreview.microsoft.com/en-us/support/redir/VA102834139.aspx
Get started with Office 365
http://officepreview.microsoft.com/en-us/support/get-started-with-office-365-HA102818409.aspx?CTT=5&origin=HA102818317
Excel 2013 video training
http://officepreview.microsoft.com/en-us/support/microsoft-excel-training-curriculum-guide-FX102828216.aspx
Make the switch to Excel 2013
http://office.microsoft.com/en-us/excel-help/make-the-switch-to-excel-2013-RZ102924304.aspx
OneNote 2013 video training
http://officepreview.microsoft.com/en-us/support/microsoft-onenote-training-curriculum-guide-FX102828218.aspx
Make the switch to OneNote 2013
http://office.microsoft.com/en-us/onenote-help/make-the-switch-to-onenote-2013-RZ102924426.aspx
PowerPoint 2013 video training
http://officepreview.microsoft.com/en-us/support/microsoft-powerpoint-curriculum-guide-FX102828217.aspx
Make the switch to PowerPoint 2013
http://office.microsoft.com/en-us/powerpoint-help/make-the-switch-to-powerpoint-2013-RZ102925029.aspx
Word 2013 video training
http://officepreview.microsoft.com/en-us/support/microsoft-word-training-curriculum-guide-FX102828210.aspx
Gesture Reference (for touch devices)
http://office.microsoft.com/en-us/support/office-gesture-reference-HA102823845.aspx
For the latest information, see the Office Resource Kit article: