Natalie asked: Are there any websites or resources available which state to a newbie what different publishing houses are looking for? (I know I'm trying to cheat here, but I thought I'd give it a go.)
www.passionatepen.com does that for romance publishers. Otherwise, you might just put the publisher's name into google with "writer's guidelines," as sometimes the house puts guidelines up on the web.
But really, the best way is to go to a big bookstore with a notebook and look at the books each publisher has for sale in your category (or, for epublishers, go to their web-sales page). Scan the jacket copy and see what's emphasized. What sticks out about the titles and premises? For example, I was recently looking for a book in a London bookstore, having read the two books I brought for the trip, and I found that Brit publishers are apparently very into Davinci Code variations, that is, Name of Famous Person + word that indicates something cool... The Shakespeare Mystery. The Henry VIII Scandal. Well, that tells me something... that I'm not going to sell to a British publisher EVER probably. (Hmm... The Jane Austen Bigamy?)
When you find a book that seems sort of like what you want to write (or have written already), open to the Acknowledgements page. (Many novels have them.) Here the author, if she's savvy and obsequious :0, has probably acknowledged her editor and agent. Note those names down. Those are the people you want to query, and maybe even mention, "This book might remind you of (title of book they edited or sold)."
Acknowledgement pages are full of great info!