Tiffany and I ramble on about differences in Crochet and Knit patterns and learn about the details of editing each.
Other Links mentioned by Tiffany:
Andrea for skill levels:
Craft Yarn Council Standards and Guidelines:
Project Levels (they do not distinguish crafts, but use the same levels for each)
Hooks & Needles, US to mm
To get to the downloadable Standards and Guidelines PDF, go to Craft Yarn Council, and select the Standards menu