I think the OP was asking about *where* to go to publicize and to whom to circulate the invitation.
bookstores (Borders Books and the like usually have a bulletin board for posting public notices)
coffee shops (same)
public events calendars (area newspapers, magazines, and radio shows often have public events calendars, including an online version)
like-minded organizations with memberships: they may agree to announce your event to their members at meetings or in electronic newsletters
Never linger too long with the ignorant,
throw stones at their talk.
Walk only with the lovers,
the mirror of the soul gets rusty when
dipped in muddy water.