As you may remember, I opened an account at Bodog Racebook a few months ago. I am really happy with it. They don't pressure you to deposit money or gamble, but it is there when you need it. It has come in handy lately, with all the Derby preps, and I'll definitely use it to wager on the Derby.
They have a 10% bonus for new accounts and a great Triple Crown page with Derby contenders, past history, track information, and Derby preps, along with some interesting Derby facts. If you haven't done so already, now is a great time to sign up.