This post is dedicated to learning Office 365 and includes various resources. I’ll keep updating this post with additional resources in the future.
Start with a free trial account
Office 365 Free Trial
SharePoint Online Administration Guide in Office 365 for enterprises
Office 365 Service Descriptions
Office 365 White Paper: Guidance for Office Development in Office 365
Office 365 Single Sign-On with AD FS 2.0 whitepaper
Office 365 TechNet Library