it's a start. probably more out there, but I'm not real big into the horse scene so these are the only two I'm familiar with. FWIW, the live feeds that are offered on these two sites are pretty reliable and somewhat easy on the eyes.
Youbet offers them free for I think 60 days. After that you have to pay for them unless you are making sufficient bets through them. Of course they don't take accounts from all states.