President-elect Obama makes it official today, announcing that Peter Orszag has been tapped to lead the Office of Management and Budget. Orszag currently serves as the Congressional Budget Office director. National Journal first reported last week that Obama had chosen Orszag.

Obama has also chosen Rob Nabors to serve as deputy director at OMB. Nabors currently serves as the 13th Clerk and staff director of the House Appropriations Committee.

At a noon ET press conference in Chicago, Obama explained what role the OMB will have in his administration in addition to its usual duties of designing and implementing a budget. "It's also going to make sure that our government -- your government -- is more efficient and more effective at serving the American people," Obama said. "And there's no better person to help lead this effort as director of the OMB as my friend Peter Orszag."

ABC News's Jake Tapper noted last week that Orszag -- who keeps a blog at CBO -- would become the first blogger to ever join the Cabinet.