Craft Forums - Craft Discussion Boards
Crafts Forum UK - Very active forum that covers all sorts of crafts and craft related discussions. There's even a board that allows you to show off your own craft projects with images.
Crochetville Forum - Very active forum that covers everything you ever needed to know about doing and enjoying crochet.
Knitting Help Forum - Very active forum that covers everything you ever needed to know about doing and enjoying knitting.
Delphi Forums - Hobbies & Crafts - Includes hundreds of hobby and craft related forums worldwide. Just conduct a search for whatever craft related topic you're interested in.
Juried Online Arts Festival: Art & Crafts Forums - Specializing in art forums with some that lead to those pertaining to crafts as well.
Crafts Beautiful Forums Homepage - A great craft forum hosted by the UK's most popular crafts magazine.
Craft Yarn Council of America Forums - Specializing in knitting and crocheting, suitable for both experienced and novice crafters.
CandleTech.com - Forums have been replaced by good quality (and complete) information about candle and soap making. Worth checking out.
CraftWEB Hot Glass Talk - Good discussion board for both the amateur and professional hot glass artisan. Active and well-maintained.