Out of all the resources posted on many blogs and on technet, I find the following link the best to kick off the learning curve:
SharePoint 2013 training for IT pros
http://technet.microsoft.com/en-us/sharepoint/fp123606
These videos are great because
- Talk mostly net new features/functionality
- Great starter for experienced SharePoint professionals
- Good depth of overview on new features and functionality
- Beneficial to site administrators/owners/contributors and not just for IT Pros
- 14 Modules with about 2-7 videos each
Roy Kim on Azure and Microsoft 365 