Wicca

Wicca is a nature grounded religion branched from ancient Paganism. It's practically impossible to know how old the religion itself is
due to numerous accounts of lost or destroyed documents over hundreds of years. So the earliest date that we can actually recognize Wicca was in 1954, when Gerald Gardner promoted the Wiccan faith despite massive amounts of Christian criticism.

There are literally hundreds of paths of Wiccan traditions, each having their separate belief. Compare this to the Baptist/Catholic/Protestant Christian, who all follow one main faith but add different opinions on their beliefs.
Most Wiccans today are called Eclectic. They do not follow a tradition per se, but they take from many traditions and use the beliefs as they see fit.
Not all Wiccans are Witches, and not all Witches are Wiccans. How can this be? In the old times, women who were handy with a hand in healing were referred to as Witches. Wiccans may use the term "Witch" as they like to define themselves, but others are quick to drop the title due to the discrimination, misinterpretation, and just downright ignorance that other faiths have expressed through the centuries.
Witches themselves have the option not to practice Wicca, but any belief that they choose. They just have that "Green Thumb" for Magick. They do not have to follow the Wiccan Rede, or any of the principles of Wicca as a religion. But a person who is Wiccan, who has that knack for Magick, can freely express themselves as a Witch. These people do follow the Wiccan Rede, and abide by all principles of Wicca.
True Wiccans practice White Magick, whereas Witches who are not Wiccan may practice all forms of Magick. There is White, Grey, and Black Magick. White Magick is used for healing and other positive influences that can only bring good to oneself or others. Grey Magick is a mix between White and Black Magick. And Black Magick is used for hexes, curses, and all other influences of ill intentions to oneself or others.
Wiccans firmly believe in Karma, or as we call "The Threefold Law". This Law basically states that whatever we send out to the universe will come back to us times three. So it is advised for new Witches to think twice, or even three times before performing a petty love spell or other Grey/Black Magick spell castings.
Wiccans are not Satanists. Satan is part of the Christian belief system, therefore Wiccans do not recognize Satan much less worship him.
Wiccans and Witches both typically own a Book of Shadows. The Book of Shadows contains the person's potion recipes, spells, or anything else related that they feel the need to write in there.
Wiccans celebrate eight Sabbats per year. Yule, Imbolc, Ostara, Beltane, Litha, Lughnassadh, Mabon, and Samhain.

Wiccan FAQ:

How do I start becoming a Wiccan/Witch? Research. Lots and lots of research. Why? You need to explore your options, look at the traditions of Wicca available to you. Find what you feel is right for you, and learn what it's about.
How fast do spells work? It depends on you. It isn't the spell that works, it's the willpower embedded in the person who's casting the spell. All the herbs, incense, candles, runes, etc are merely "spell additives" to help you stay focused and give you the confidence to achieve your goal. Don't expect anything to happen overnight.
What kind of materials do I need to get started? A Book of Shadows is a great start. You can order the traditional ones online, or you can use an ordinary notebook. Then get your spell book started, fill it to the brim with information. Other materials that you should have on hand: Incense, candles, herbs, runes, crystals, and an athame. The first two are needed the most, everything else can wait until you get more experienced unless you're huge on circle casting, then you may want the athame.
What should I do to prepare before I attempt a spell? Get your altar together, and meditate. Obtain a good state of mind, because your concentration and willpower mean everything in obtaining your goal. Incense and candles are mostly famous for their Aromatherapy qualities to put you in a good spell casting state.