Applescript for Absolute Beginners
This is a free, online textbook that can be downloaded as a pdf. According to the author, "Learning how to script with AppleScript is ideal as an introduction to programming. It leaves out most of the nitty-gritty work a programmer in a computer language such as Java has to do before she can even perform the easiest of tasks. AppleScript is easy enough that a 10 year old can learn it, yet so powerful that professionals enjoy it too. That leaves plenty of room for growth for you."