Wiccan spells are often characterized into two major types, "White magic" being associated with good and benevolent aims and "Black Magic" often associated with evil deeds and satanic worship.
Many modern Wiccans have stopped using this duality, arguing that the color black is just another color that has been dramatised by Hollywood, and that the color itself should not have any associations with satanic ritual or evil at all.
Wiccans believe that magic spell casting is a fundamental law of nature. A law that we have yet to completely understand. Other believers of the Wicca Religion do not claim to know how their magic works at all, it is enough that it does work and that they have seen it work for themselves.
Wiccan spells or Wiccan Magic is defined by most Wiccans as "the art of causing changes to occur in compliance with one's own will". The term Wiccan, simply reiterates to anyone who practices the Wiccan Religion.
A Wiccan spell is a practice or ritualized event which leads to measurable changes in the physical or emotional sphere in accordance with the intentions of one or more Wiccans who are casting the spell.
Wiccan magic spells typically involved include love spells, healing spells, fertility spells as well as spells to help remove any bad effects.
The Wiccan Sacred Circle
Wiccans often cast spells during ritual practices inside of a construct called "The Sacred Circle", in an attempt to bring about changes to their world.
A Sacred Circle is a circle or sphere of space marked consecrated by Wiccans to either contain energy and form a sacred space, or to form a barrier of protection. The Sacred Circle can sometimes be both.
Sacred Circles are created by making a ring from salt or chalk. Some Wiccans will even scratch a line in the earth and in some cases it can simply be visualized by a Wiccan Witch to produce the same results. Similar circular constructs appear in some Eastern religions
Wiccan spells, in the majorities of instances are cast to help material a benevolent exit. The truth is the majority of magic spells cast by Wiccans (as well as many other believers and advocates of the "Old Religions")) are cast for good and not evil.
The Law of Threefold Return
This is demonstrated by the Wiccan Rede, which simply states "an it harm none, do what ye will". Many Wiccans also believes in another element of Wiccan morality which is "The Law of Threefold Return".
This law holds that regardless of what type of Wiccan spell is cast, be it benevolent or malevolent, the actions of the spell will return to the practitioner with triple the force or power.
This belief is very similar to the eastern philosophy of Karma, first espoused in ancient India and later appearing in various forms in the Buddhist, Jain, Sikh and Hindu philosophies. This is one reason why Wicca is regularly referred to as the yoga of the west.
Yoga, itself is one of the six schools of Hindu philosophy. Yoga is about discipline and training working together to help the consciousness reach a state of perfect spiritual insight and tranquility. Many modern Wiccans will view this statement as a fair definition of their belief systems too.
Wiccan Spells come in many types and variations, so long as you practice your spell casting with a good and benevolent mental attitude, you will find like many of those old nature religions such as Wicca can be rewarding and as fulfilling as many more eastern and western belief systems.