Abingdon Press is launching a Christian YA line in 2014 and is looking to acquire in early 2013 high-quality books written for 14 to 19 year olds; would especially like to see series books as well as steampunk, medieval fantasy and urban fantasy. They note on their website that they accept submissions only through agents or from writers who meet with their editors at conferences, so if you don't have an agent you might want to see if you can swing an editor appointment at one of your local Christian writer conferences.
OakTara wants to see Christian YA fantasy, sci-fi, realistic fiction, medieval fantasy series aimed at boys, issue fiction and teen writers; they are eager to acquire "really good" teen writers and fiction written for male readers. They do accept unagented submissions, see more about their guidelines for writers here.
(Notes on both of these sub ops were found in the August 27th issue of Publishers Weekly; I chased down the links myself.)