[@Thantos] Well, there are many types of werewolves out there. 
Some will transform by force when the moon is full while it's optional for others. Some can transform at will at any time.
Some transforms fully into a wolf, some into a hybrid between man and wolf, some barely transform at all. 
Some gain their powers willingly through magic or a "contract" with a god or demon. Some are bitten by another werewolf and thus cursed. Some tries to give a natural explanation for the phenomena. 
Some regain their human intelligence in wolf-form, while some give most of it up. 

This is just what I can think of as I sit down and write this. I'm sure there is more.