The tarot is a form of divination, but it is not fortune telling. It is helping someone to understand themself and the situation they are in. It can give information about what is going on around a person, and help for which path to take, but it isn't going to say "You will die soon" or "You will win the lottery in two years on so and so date". It doesn't work like that.
There are three different types of cards in a tarot deck, the major arcana, the court cards, and the four suits.
The four suits in a deck are swords, pentacles, cups, and either wands or rods. Each suit is a different element, swords are air, pentacles are earth, cups are water, and rods are fire. Each suit goes from ace to ten. The names of the suits may vary between decks, but they are in essence the same.
The court cards consist of a page, knight, queen, and king in each suit. The titles may vary from deck to deck as with the suits, but the meaning of the cards remains the same.
The major arcana consists of 23 cards, with various names. This is where you find the most well known cards, the hangman and death. You'll also find cards such as judgement, the star, and the lovers.