Would you believe there's already a thread, started in 2001, called Lyr Req: Knitting Songs?

Here are a few songs that have already been posted, in various threads:

Knitting and Crochet

Knitting, from Arthur Askey

The Knitters, by C. Fox Smith

Ghost Knitters by the Road, (a parody)

Mother's Sitting Knitting Little Mittens for the Navy