Attached Link: http://www.3-darena.com

Well Lemurtek has a range of animal/human characters available over at 3-darena for free, there's a centaur at www.nerd3d.com, and mermaids can be found at www.dacort.com in both free & pay flavours. Check the tutorials link at the top of the page, I'm pretty sure you'll find a tut for doing it too. Rob