The National Needlearts Association (TNNA) has many useful blogs and webinars:

The American Crafts Council (ACC) is a non-profit that preserves, cultivates and celebrates craft.   Their website is a useful reference for finding museums, workshops, and organizations dedicated to craft.    

The Craft Yarn Council (CYC) represents leading yarn companies, accessory manufacturers, magazine and book publishers and consultants in the yarn industry.  They sponsor promotional and educational programs, and worked with others in the industry to set up a series of guidelines and symbols that brought uniformity to yarn, needle and hook labeling, patterns and yarn labels.

Explanation of the commonly used yarn and weight system is available at: