Like any other publisher:
Have you personally ever read any of their books?
Have any of your friends ever read any of their books?
When you walk down to your local bookstore do you find any of their books on the shelf?
If not ... why are you considering them?
Start at the top and work down is my advice to everyone.
That means starting with the imprints of Bertelsmann, von Holtzbrinck, News Corp, Viacom, Time/Warner, Houghton Mifflin, Pearson, Harlequin, John Wiley, and Bloomsbury. Go to those corporate webpages to find the names of their publishing houses. Go to those publishers' webpages to find the names of their imprints. Go to the imprints webpages to find their submission guidelines.
Most (but not all) will require that you submit through an agent.
Here's how to get an agent:
http://www.sff.net/people/VictoriaStrauss/agentsearch.html
http://www.neilgaiman.com/journal/2005/01/everything-you-wanted-to-know-about.asp