These instructions, directions, and suggestions above are meant to provide the novice user with some useful guidelines for beginning to use mediation and moderation. You will find that there are other issues involved with these techniques the more you use them. For example, as noted above, how does one perform a mediation analysis with longitudinal data? How does one perform moderation in multilevel modelling? And so forth. I have addressed the full range of issues concerning mediation, moderation, and hybrid models (that involve both mediation and moderation) in a book that was just published in April, 2013. I dedicate one chapter each to basic mediation and basic moderation techniques (like I have done here), but I also have written additional chapters to explain more sophisticated ways to conduct mediation and moderation. I specifically wrote the book with numerous data-based examples to assist in the learning process, and I think that both beginners as well as more seasoned researchers will find much to appreciate in this book.
I recommend that you Google the book and check out sections of it before you decide to buy it or not, and read reviews for the book as well. If, after all of that, you think that you can benefit from having it, then you can buy it through your local book store, or on-line from these two sources: