Principles of Surgery (brilliant! - must visit)
Information for Pre-Vet students (very useful)
VetNet (The Veterinary Information Network)
VetNet UK
The Royal College of Veterinary Surgeons (UK)
World-Wide Vet

The Cat Fanciers association (Lots of Good Info Here)
Animal Rights - The Mining Co. (Ethical issues)
AVAR (Association of Veterinarians for Animal Rights)

A very good site - now you find out how squeamish you really are! - Includes Videos.

Find more Pre-Vet clubs than I can list on this page.

Some of the pictures on this page come from their associated sites.  Full credit for these pictures should therefore go to the linked site.