I chance upon an archived blog of Abraham Olandres where he talked about creating a PHP+MySQL email tutorial where he cited what I've done as an example. Actually, I first learned of the idea from Shery's DailyWrites site. To date, I have three workshops online hosting it at GetResponse.com.
Creating an online workshop helps you generate a good database as well of targeted individuals who you have assurance of their interest in the subject.
Were you able to create an email based tutorial? How was the experience?