large plastic or metal needles
The yarn, scissors and needles can be changed as necessary to suit the age of the person you're going to be doing the weaving with.
Young children and those with poor motor skills will benefit by using very large plastic needles and thick yarn as it will be easier to handle. Advanced crafters/weavers can use finer needles and yarn. :)
I'm using Lion Brand Yarn bonbon
yarn for this - it's really fine so it makes the finished weaving look really nice. :D