SB Nation has recently entered into a partnership with Youbet.com to provide a live racing interface where you can find entries, live odds, carryovers, results, and live video for a selection of tracks each day. All the information on the "Live Racing" site is free and can be viewed even if you don't have a Youbet account. If you want to wager and aren't a Youbet member (and you live in a state where ADWs are legal), there is a link to easily sign-up for their free membership.
I've also included a link to the Youbet live racing page over on the left side bar under "Racing Links".