As mentioned in my update to our post about the Doctor Who 50th Anniversary children's e-book series, Artemis Fowl's Eoin Colfer has officially been confirmed as the first author participating in the project. His story, "A Big Hand for the Doctor," will be released on January 23. Earlier this week, The Guardian posted a 2-page excerpt from the story; it may be read here.
“London, 1900. The First Doctor is missing both his hand and his granddaughter, Susan,” reads the official story synopsis. “Faced with the search for Susan, a strange beam of soporific light, and a host of marauding Soul Pirates intent on harvesting human limbs, the Doctor is promised a dangerous journey into a land he may never forget…”
There has yet to be another author officially linked to the project; Neil Gaiman seems to be participating, though.