These resources are presented in no particular order, and without specific endorsement. In other words, your mileage may vary!
Online Design Classes
Stitch Charting & Design
**Indicates crochet charting, either along with or instead of knit charting
**Adobe Illustrator (not stitch charting software, per se, but a powerful graphics program and industry standard)
**Inkscape (an open-source vector-based drawing program)