Try picking up a copy of the Writer's Market. It's a big thick book that lists about a zillion markets for writers. It's not cheap though...I think about $40.
There's also a copy of the most recent Writer's Digest, or Guide or whatever they call it at your local library. Just remember, whoever you contact, make sure you do your research. If they want a query only, then don't send them a synopsis and three chapters. And a tip -- find out who the acquisitions editor is and put their name at the top of the query. Don't address it to the owner of the company. That only shows that it wasn't worth the time for you to do your homework. It's all about business, and we, as authors, have the obligation to learn all the aspects of it, just as any other businessman would.