Horror podcast Tales to Terrify (now up to its 41st episode starring work from Tim Lebbon, and still going strong, with its first print volume forthcoming) is open to submissions. If you want to be part of this stellar show, read the submission guidelines at the site.
Previous shows have featured HP Lovecraft, Stephen King, Margo Lanagan, Kaaron Warren, and a truckload of other talent, so you would truly be aiming to keep good company with your submission. Good luck!
(On a personal note, this is my favourite horror podcast. Period.)