In co-operation with Critical Path Training, Microsoft has released a massive amount of videos and excellent content for new customization capabilities for SharePoint 2013. You can find the traininghere ..
Introduction to Office 2013 and SharePoint 2013 development
SharePoint 2013 app model for developers
SharePoint 2013 developer tools
Create hosted apps in SharePoint 2013
Create cloud-hosted apps for SharePoint 2013
SharePoint 2013 client object model (CSOM) and REST APIs
OAuth and application identity in SharePoint 2013
Develop SharePoint 2013 remote event receivers
Workflow changes and features in SharePoint 2013
Business Connectivity Services changes in SharePoint 2013
Search features and changes in SharePoint 2013
Enterprise content management changes in SharePoint 2013
Web content management (WCM) changes and features in SharePoint 2013
Social features in SharePoint 2013
Office services in SharePoint 2013
Create mobile apps for SharePoint 2013
Project Server 2013 training for developers
I’ll also be creating a series of videos in Arabic. I’m planning to release some in Jan 2013.
Ayman El-Hattab's Technology Blog 