AWAI's Graphic Design Success program (which is no longer available in the form that I had bought it...they use something else now) is what gave me my start.
It was a great first-step into the world of DM design, but like anything else, you've got to continue that education through other sources to keep progressing. (Not to mention the software training required to properly use programs like InDesign, QuarkXPress or Photoshop.)
I've been on some "normal" design forums and some people openly mock DM design as not "real design".
Ok...less competition for work, I suppose.
If you have design-related questions as you're working on a project where you're having to handle the design, feel free to ask... no strings attached.