Writing History, Yale’s Group.
Georgia Writers’ Bloc, University of Georgia’s Group.
The Narrative Nonfiction Working Group at UIC.
Past Tense Seminar, sponsored by the USC-Huntington
Early Modern Studies Institute (which extends well beyond the early
modern period).
The Making History Podcast archive offers all sorts of musings on writing and technology, as well as interviews with prominent historians. You can also find podcasts of the Past-Tense Seminar meetings here.
Historians are Writers! 