Here is SimiliBridge, a free program made in the hope of helping the great majority of people to learn bridge. This first version only includes the minibridge option and therefore is particularly written for beginners who have never played bridge, or for those who have just been introduced to minibridge.
The program suggests that you start by playing rubber bridge like you would do with the family or friends, when there are only 4 players. This kind of short game is really the best way to begin with, since you can win a game with a bit of luck, what beginners do appreciate generally. But you'll also be able to play a fixed number of deals like people do in bridge or minibridge tournaments, and by comparing your scores with the computer's ones, no doubt that you'll improve your playing rapidly.
By default, the players have the level of someone who plays his first deals. But as soon as you gain confidence, feel free to check the playing technique options accessible by the rule preferences. Once you have understood a technique (some help pages will explain them to you), enable it so it can be applied by the other players too. This is the way you'll learn the basic techniques of the game and will soon become a real bridge player.
The whole program is in English, but the help pages and the example deals about the playing techniques are still in French and will be translated within the coming year, sorry about that.
Stick at it a little bit if you find the game somehow difficult at first sight. And contact me if you don't understand something or cannot make progress. I will be very pleased to help you.