One of the most indispensable tools for any freelance writer is a copy of the current Writer's Market. I believe you can also use their website, but I haven't checked it out.
Have any of you used the website? I know that as far as the book is concerned, it contains listings of every place in the nation (and otherwise) where you can get something published. It tells you who to contact, whether they take things without inviting you to submit, and if they'll pay you. The book tells you what your chances are of getting published there.
It can save you a lot of time and energy.