Candice is right, submit your manuscript to more than one publsiher. Just make sure that you check the publisher's guidelines and verify they take simultaneous submissions.

Many publishers won't accept unsolicited submissions so to save yourself some postage and paper, submit a query letter first. Put together a solid synopsis that you can use to submit as well.

Most publishers (and agents) - if they're interested - will request the entire manuscript only after reading your query and synopsis.

I recommend that you submit as many queries as you can. Good luck!