Witchcraft = a *craft*, a set of skills relating to spellcasting, not dependant on any religion.
There can be Christians who practice witchcraft, Pagans who practice witchcraft, Jews who practice witchcraft, Catholics who practice witchcraft, Santeros who practice witchcraft, Wiccans who practice witchcraft, Bhuddists who practice witchcraft, etc. People from all ethnicities, all religious persuasions, and all parts of the world practice witchcraft - not just Neo-Pagan/Wiccan types.
At least this is my definition. Your mileage may vary.
In my views, its not a religion.
Not all use gods and goddesses in their craft.
I see it as a craft, lifestyle, and that such.
A religion is a belief system. Considering each practitioner has different views on the craft, I wouldn't consider it a religion either way.
Religion usually implies worship of a higher entity, and while different deities are a part of witchcraft, not all practitioners choose to worship them. Some just accept them as friends and others ignore their existence completely.
Wicca is most definatly a religion.
While the average person on the street may not know the difference between practicing magic and being Wicca, you will find most people on here do.
I myself and a druid and not a wiccan, but I still practice the craft, adding more evidence to the fact that there is a difference between them.
To me Wiccanism is both a religion and belief, becuase you have the Wiccans and the Ecclectic Wiccans.
Wiccans=Religious
Ecclectic Wiccans=Belief or Followership
I would call Wiccanism both a religion and belief and witchcraft a doctrine because it's such a broad term.
I've heard Wicca be called a religion, but honestly, I see it more as a Spiritual Path. Its like that question, are you more religious, or spiritual? The Wiccans I know would consider themselves more spiritual rather than religious. Also, the whole idea of it being a Spiritual Path just makes me think there is more room for open expression and free flow, rather than set religious ideas. Then again, I know Wiccans who treat it as a religious faith, so, I guess that could be one of the many reasons they take initiations, lineage, and trad ethics so seriously, thus like a religion. I guess it really goes by the practitioner.
And witchcraft, the craft of the Witch or Wise one, is a worldwide used term. In my eyes, it can be practiced by anyone under the right beliefs and ideas, because it ties into magick, and magick is in fact behind and coursing through all religion and spiritual faiths. (Its why I say everyone can and does work magick in their own way) This is a craft, like an artform.