If you want to try out a pattern or two, but don't necessarily want to invest in pattern books, there are lots of great free resources online. Here are just a few or the ones I really like:
Lion Brand Yarns: While it requires a free registration, you will have access to loads of patterns. There are lots of adorable amigurumi patterns, along with afghans, clothing, accessories and home decor items.
RoxyCrafts.com: This is Tamie Snow's home on the web. You can find both crochet and knit patterns, her blog, and patterns for sale.
Free Amigurumi Crochet Patterns: This is a great resource blog for patterns scattered all around the web. There are more than just adorable animals, there are also patterns for food, dolls and other toys.