To find practicing witches in your area, you can try a phone directory, search under Pagan Churches or Wiccan Groups, or send $2 and an SASE for a listing of organizations to:
COG Correspondence Officer P.O. Box 1226
Berkeley, CA 94701
COG, Covenant of the Goddess, is a U.S. umbrella group that aids and assists local pagan chapters all over the country.
You can also contact them through e-mail at firstname.lastname@example.org or visit their website.