Two notable DITA tutorials have come online recently. In the “getting started” category, the tutorial at http://www.lone-dita.com provides a introductory overview of DITA. It was compiled by a member of a small documentation team as result of their effort (successful, I presume) to deploy DITA. The tutorial is concise, yet surprisingly thorough, covering DITA topic types, maps, conrefs, metadata filtering, and the DITA Open Toolkit.
On the other end of the spectrum, fellow DITA Technical Committee member Eliot Kimber has created a tutorial on the subject of DITA specialization. I often find specialization to be more challenging in practice than in theory, and Eliot’s tutorial is a welcome resource.