Of all the regionals, I believe ACA is hiring the most. When I went by pilot recruiting a month ago, the board said they were hoping to hire 320 this year. Two week ago, I stopped by and it had been upped to projecting 370 this year. To all those interested in ACA: keep updating. Knowing somebody here helps, but an interview captain told me we are interviewing 3 days/week at present, soon to be 4 days/week, so keep on sending your stuff in and keep your fingers crossed.
Of the other regionals, I believe SkyWest is doing hiring, though I hear they prefer people with 135/121 or 'mountain' or 'west of mississippi' flying. Comair was hiring, they may have slowed down. Look for ASA to possibly pick things up later this year. I believe they are interviewing right now.
Good luck to all.
JTrain