http://airlinepilotforums.com/showthread.php?t=12314
The interview is pretty standard. Written, Sim, & Face-to-Face with HR & Capt./FO. I have heard & read that some of the interviews are being conducted at headquarters in Manassas meaning no written/sim. AviationInterviews.com & WillFlyForFood.CC will square you away with more of the specifics.
Try to relax (easier said than done in some instances, I know) and just be personable. Be yourself and be honest. If you deserve the job you'll get it.
Keep asking questions if there's ANYTHING else you're interested in knowing.