PBS is currently running a program on pattern drafting. I missed the first one but I have found it here on YouTube. In Toronto it's on Monday's at 2:30. Check your local PBS listings for your location.
I know most of you aren't interested in drafting your own patterns, however I'm going to suggest the benefit to understanding the process is it will help you to create better fitting sweaters. I think many of us struggle with the translation from a flat pattern to a three dimensional sweater. The demonstrations in the program will help to improve your understanding and give you skills for analysis when things go wrong so you can avoid those problems on future projects. This show targets sewers so some of what it includes may not be of interest. In this episode the first 20 minutes are very informative for knitters. If you hang on to the end host Peggy Sagers demonstrates dart rotation from bust and vertical darts to a French dart. Darts can be rotated to any location and may be reformed as gathers or tuck instead. So don't assume that garments without visible darts don't include shaping.