They make up quite quickly. You just need yarn, a crochet hook, stuffing and safety eyes because at Lion Brand Yarn they have a endless selection of free patterns for amigurumi. You do have to sign up for their site, but I've personally never had a problem with them (ie they don't share your email) and I like getting their occasional email updates (which are easy to opt out of, if you desire).
Type 'amigurumi' in the Search box, sign in and enjoy all the free patterns! Here's some pictures of some of the adorable critters you'll find here.-C