I don’t know any good computer baccarat games, but if all you want to do is to learn to play it, you can find a good rundown of the game in Ian Fleming’s Casino Royale. Or any good book on card games or gambling (Scarne is good for this kind of thing) can give you the rules, although not in such an interesting manner as Fleming describes.
Rather than a computer game, I’d suggest getting a rundown of the rules and a deck of cards at home. The game is quite simple to play, and as a player in a casino, you don’t really “play” baccarat at all, at least not in the blackjack sense. In baccarat, the rules are specific and dictate everything that happens, meaning that (unlike blackjack) play is not dependent on the players’ decisions.
Briefly, the dealer pulls cards from a shoe, making a Bank hand and a Player hand. Whichever hand totals nine or gets closest to it wins. Picture cards and tens count for zero, and if the hand total goes over 9, the first digit is discarded (for example, a hand totalling 13 would be a 3, a hand totalling 16 would be a 6, etc.).
As a player, you just bet your money on either Bank or on Player (in the casino game, they’re just names; they might as well be called Red and Black, like roulette) and wait for a decision. If you bet Player and it wins, you win too. If you bet Bank and it wins, the house will deduct some of your winnings as a commission. This is how the house makes their money on the game.
That’s about it, really. If you can find a computer baccarat game, this somewhat-confusing explanation should be clearer, but if not, I think I covered the main points. And no doubt, the casino will be glad to explain the game further and perhaps offer a lesson or two. Good luck!