Equination 
In this horse sim game you can buy, sell, auction, breed and race thoroughbred horses for prizes.
http://www.equination.net/Web Runners
A horseracing game where members race Thoroughbreds on dirt or steeplechase. Introduction and overview, a message board, online horse records, a chat room, archived race results, and a hall of fame. A waiting list of new members is used when needed.
http://www.webrunners.org
Final Furlong
An automated simulated horse racing game where members can own, train, race, breed, buy, and sell fictional Thoroughbred racehorses racing on dirt, turf, and steeplechase all year round. 15 races are run twice a week (total of 30/week). FAQs, message board, site history, and login for members. Member login includes stable overview, purchasing/breeding horses, searching for horses, entering races, viewing race results, and hall of fame.
http://www.finalfurlong.org
Tipster Challenge
Free Horse Racing Tipster Competition. Competitions in Betting Challenge, Nap Competition, Tipster League, Champions League, Tipster Cup, Major Race Events, Ten To Follow. Competitions are based on UK racing.
http://www.tipsterchallenge.com
