Here is a collection of helpful lessons and tutorials on Email basics that I found:
So far, this is my favorite one of the bunch: Learn the Net: How Email Works. Covers lots of topics and explains the hows (how something works, what to do, etc). 17 different topics. I thought these were nicely written.
Email Basics: Ten lessons and a quiz. Lists objectives for each lesson and has movie clips. This one is a good one too.
E-Mail Basics > Overview – Key Ideas: Not as fancy, but good too. Has activities and “pop” quizzes.
“Short course will teach you the fundamentals of e-mail, a skill that has become the most popular use of the Internet.” Has review questions and quiz.
Email Basics: This links to a collection of email related articles (how to’s at E-How).
Internet E-mail Basics. Super plain but does have a few activities usually after each reading.