There is lots of valuable information – particularly for developers – on the Wiki pages of the OXID forge, as well as a download area for older versions, update packages and release notes for the CE version.
Planet OXID is an aggregator for all blogs dealing with the subject of OXID. You’ll find announcements, module descriptions and tutorials from bloggers here.
This is where you‘ll find tutorials if software concepts are introduced or modified, as well as how-tos for specific requirements. Feel free to share your knowledge in this Wiki category.