DotDotSmile has lots of fun knitting needles and crochet hooks, like these pencil knitting needles (available for $12.50). These would be perfect for a little one just getting started with knitting.
These knitting needles by Pony have dull tips and come in pairs of alternating colors to help your little one learn to knit. You can pick up a set at Purl Soho for $4.50.
This knitting doll set is perfect for younger children that may not be ready for a set of knitting needles. It allows children as young as four to knit cord that can be used for things like friendship bracelets and finger puppets. Available for $6.62 from My Crochet on Etsy.