Rabbis are permitted (and often encouraged) to marry. The same rules apply to rabbis as to other Jews, although they are usually respected for their knowledge. Historically, rabbis would also act as judges for their communities.
Most denominations of Judiasm permit women to be rabbis; the exceptions are the Orthodox denominations. One denomination, Karaite, does not believe in rabbis or their interpretations of the Torah as a guide to practice.
In the U.S., they are usually hired by the congregation and lead it much like a preacher, minister or priest would a Christian congregation.
- the article on Rabbis from the Jewish Virtual Library