Ferret Central
An excellent place to start learning about ferrets is The Ferret Central Website. There are FAQs, medical information, cute pictures, and links to other ferret-related sites. These sites can link you to other sites, which will link you to - ah, you know how that works. Ferret Central doesn't get updated all that often, but the Ferret-related FAQs are possibly the best on the 'Net. That is why I recommend this site.