I agree that the Writers & Artists Yearbook is valuable. You can view a copy in the library, and don't forget to check the addressee details are up to date before sending enquiries. In my experience, most publishers prefer to deal with Agents, but check websites and a quick e.mail helps. I have found that researching and submitting letters to magazines and journals is quite rewarding. If you incorporate humour (where appropriate), current topics and refer to previous articles, they often get published, and sometimes even lead to a request for more contributions. Always follow submission guidelines, send the material to the relevent publisher/agent, expect a wait, and if your aim is to be a published writer do your market research and write what people want to read!