An article in Inside Higher Ed, which was origianlly forwarded by Dr. Horwitz:
http://www.insidehighered.com/advice/2011/02/24/essay_on_whether_you_should_teach_online
This article introduces some useful resources.
Diana Hacker’s interactive website, A Writer’s Reference, which is meant for both teacher and student:
http://bcs.bedfordstmartins.com/writersref6e/Player/Pages/Main.aspx
plus
Scott Warnock's book Teaching Writing Online: How and Why:
https://secure.ncte.org/store/teaching-writing-online
The blog of this article's writer, Chloe Yelena Miller, A Writer & Writing Teacher's Blog: Inside Hints:
http://chloeyelenamiller.blogspot.com/