Wicca isn't organised in any broad way. There are small groups, called covens; but these are like, a dozen people. When they get sizeable, they "hive off" into other ones, and lineage can be traced through this. Lineages are called "Traditions", e.g. the Gardnerian Tradition, which is the oldest British Wiccan sect. But Traditions are rarely organised together in any formal way. Within a coven, though, there is a hierarchy system; three degrees of priests, with a high priest or priestess leading services and rituals. Traditionally, there are an equal number of male and female priests, and an HP/HPS whose gender depends on the group's preference.
Furthermore, the majority of Wiccans today are solitary practitioners- not part of any group, but using public material to practise Wicca on their own. The trouble with that is that a lot of practitioners don't know what they're doing, and instead free-wheel it; claiming bullshit like "Wiccan can be anything you want it to be". This irritates me, because I have done extensive research into Wicca's history and traditions. Too many solitaries have total disrespect for the things that make Wicca what it is.
Oh, and if you want to know more about that issue, I recommend
this site. It's very informative.