BIOLAB - http://www.biolabsoftware.com/

Biolab is a Web 2.0 tool which gives students and teacher access to online disections. This can be very useful for low budget school, children who would not be able to handle a real disection (Physically or emotionally), or just to create a greater understanding for the students. This site offers a variety of animals to disect, perfect for varying levels of education, they offer everything from flies and frogs to Cats and pigs. 

It provides an in depth study of the anatomy and physiology for the older highschool grades with comparisons between human and cat for example.

This site is very resources as it offers suplemental teaching materials like crossword puzzles, worksheets for students and tests and quizzes.

There seems to be no restrictions on use.