Horse Betting

[HajiShirazu]

Since horse racing is legal and all to bet on online, I figure I might start trying to learn a new game. Of course like poker I don't expect to head out to the track and crush the pools right away, and actually would be happy simply being a modest winner. I really like horse racing, I have spent hundreds of hours playing Winning Post 6/7, a Japanese horse simulation game (greatest game ever, so good it's worth learning the language to play), which I know has nothing to do with ability to beat the sport.
Anyway, first question, is horse racing really beatable? I assume yes as I hear of tons of pro handicappers, but I know lots of "big winners" at poker as well, and isn't the vig like 20%? I also hear that you can get rebates betting online, what sites offer the best rebates/lowest vig/best bonuses/etc. for US players? Are there any good reasons to bet live over online?
Second question, if it is beatable, what are some books/sites to read to get started? I know that all these "system" and tout sites are almost certainly total BS, but what are the best online information services for people looking to cap themselves?
What kind of time committment does it take to be successful at this? How long does it take to become a winner from someone just starting out? If you are a pro/know pros well, a description of the type of schedule you go through in terms of research and betting would be totally awesome.
Any other tips you would have for people starting out in handicapping would be great as well.