The official word is no hiring for 2011. I wouldn't be surprised if Delta held interviews in the Fall of 2011 for early 2012 staffing. However, once hiring starts, it will not stop for over 15 years, since we're facing the loss of over 7,600 pilots in that time frame.
Oil over $100/barrel & the Tsumami/nuclear disaster in Japan slowed things down temporarily. It can start up just as quickly, so be ready.