Chris Ross, PhD grad of University of Edinburg and operator of The Daily Scroll and Sic et Non, has written an excellent piece on common courtesy for e-mail communication geared to pastors but applicable to all! See his post, For Christ’s Sake, Hit Reply.
Incidentally, on Sic et Non, you have a chance of winning some major Bible softare! Check out the site for more information!
Working out Salvation with Fear and Trembling 