You're made a very big request. I doubt anyone is willing to provide you a content layout for a 6 hour training session. I'll make just a brief comment.
Since you want to cover email in this presentation, I suggest you explain the difference between webmail (accessing email via web browser) and using an email client such as Outlook Express, Outlook, Windows Mail, Windows Live Mail, Thunderbird, etc.). Webmail includes such well-know free email services such as Hotmail (Microsoft), Yahoo! Mail, and Gmail (from Google), and webmail includes any other email services that can be accessed via web browser. For example, I can access my primary email account, the account provided by my ISP, either via web browser, i.e. a webmail interface, or I can set up my email in an email client and use it to get my email. The latter is possible because the email account is available as a
POP mail account.