This video explains how to wind a ball of yarn (primarily for the purposes of the knitter) so that you can take the end that is on the inside and the end on the outside and knit them as a double strand.
by Arts and Crafts
by Virginia Galligan
by Sense & Sensibility Patterns
by New Stitch a Day: Knitting and
by ArJeiEmSi (Tele-VISION)