A recent email from Poets & Writers included a link to their Contest Submission Calendar. Handy, but not all-inclusive – for instance, the Amazon Breakthrough Novel Award (into which I entered my urban fantasy this year) is not listed.
Poets and Writers also provides a database of literary magazines for poetry, fiction and creative nonfiction, and a list of small presses.
Another extensive database of publishers is at www.Duotrope.com - 2350 current markets for poetry and fiction – from flash to novel length.
Wikipedia’s list of publishers is alphabetical, and not grouped by genre, so you really have to do your research.
A good way to keep up with latest book deals is through Authorlink or Publishers Marketplace. Sign up for their free daily newsletter – or search for a publisher or agent. Of course, many publishers only accept agented submissions – before contacting any agent, do your homework! Check the Preditors & Editors list for warnings. The Science Fiction and Fantasy Writers of America posted guidelines for newbies. Poets & Writers also posted guidelines for choosing a literary agent.
Be leery of any go-between service charging fees such as Publishers and Agents.
Author Gabrielle Luthy has a great list of publishers, agents and related articles and writer resources in general.