off the top of my head.....

Allegiant -- Hiring
Air Tran -- recalled and hiring
Atlas -- recalled
American Eagle -- recalled and hiring
Kalitta Air ( rumor only ... may have happened just in the past day or so..)
USA Jet -- recalled and maybe hiring
Express Jet -- recalled some
AWAC -- recalled
Horizon -- recalled some

probably others as well....
Colgan
RAH