Jan. 21, 2009 -- On his first full day in office President Obama froze the salaries of his senior staff and imposed tough new rules for lobbying and for releasing public information.

The president will move quickly to close Guantanamo prison, the controversial detainee base in Cuba started by the Bush administration. ABC News has learned Obama sent a messenger to Capitol Hill to brief members of Congress on orders he plans to sign tomorrow closing the base within a year.

Obama woke up in the White House for the first time and began a whirlwind day, having already set in motion Tuesday major policy changes for the new administration.

On his agenda for Day One, Obama summoned his economic advisers to hammer out details of an economic bailout and called in his top generals to give them new marching orders.

His staff was already putting into effect executive orders to usher in the Obama presidency, as well as his request that military hearings for terror suspects at the Guantanamo prison be suspended for 120 days.

But at a staff meeting to swear in top aides, Obama dropped a bombshell. He was freezing their salaries.

" During this period of economic emergency, families are tightening their belts, and so should Washington," Obama told the assembled staff.

He thanked the staff for accepting the restriction and said, "It's a mark of your commitment to public service."

The president said the salaries of everyone on the White House staff that exceeded $100,000 would be frozen. If the Obama White House pay structure is similar to that of the Bush White House, more than 100 staffers will have six-figure salaries.

Obama went on to spell out restrictions on lobbying after employees leave the White House and vowed that the federal government would be more willing to make information public.

The president said he was issuing the "rules of the road of my administration" to "make government more trustworthy in the eyes of the American people."

"There is too much secrecy in this city," he said. "That era is now over... Information will not be withheld just because I say so."

The adrenaline of taking over the Oval Office must have kicked in, because despite Tuesday's grueling pageant of ceremonies in the numbing cold, and dancing at 10 inaugural balls until 12:55 a.m., the lights snapped on in the residential quarters of the White House before dawn today.

Obama entered the Oval Office for his first day of work at 8:35 a.m. and got to spend 10 minutes alone before the demands of the nation began to demand his attention, White House spokesman Robert Gibbs said. During that time, he read a note left to him by former president George Bush that was addressed, "To #44, From #43." By tradition, notes from the departing president to the incoming president remain secret.

Then the work began. At 8:45 a.m. Chief of Staff Rahm Emanuel entered to discuss the day's busy list of events, and by 9:10 a.m., first lady Michelle Obama joined her husband in the Oval Office.

Obama dove into the thorny Middle East right away, placing phone calls to Israeli Prime Minister Ehud Olmrt, Palestinian President Mahmoud Abbas, Jordan's King Abdullah, and Egyptian President Hosni Mubarak.

Also demanding his immediate attention are Senate confirmation proceedings today for two key Cabinet posts, Secretary of State-designate Hillary Clinton and Treasury Secretary-designate Timothy Geithner.

In between, Obama attended a National Prayer Service at the National Cathedral, sharing a pew with Vice President Joe Biden and his wife, along with former President Bill Clinton and future secretary of state Hillary Clinton.

During the afternoon, Obama hosted an open house of his new home, telling visitors to roam around, just don't break anything.

Even during the balls on Tuesday night, Obama was plotting his first steps today.

"Starting tomorrow, we'll be making a series of announcements both on domestic and foreign policy that I think will be critical for us to act swiftly on," he told "Good Morning America's" Robin Roberts at the Neighborhood Ball. "We're not going to be able to delay."

As Obama charged through the long and emotional day Tuesday -- from attending a private church service in the morning to delivering his inaugural address to dancing well past midnight -- much of his staff got right to work.

Just hours after Obama took the oath of office, Emanuel sent a memorandum to federal agencies and departments, calling for them to halt pending regulations until the Obama administration reviewed them.

Top Priority Is Faltering Economy

The new president's biggest priority will be reviving the faltering economy, and that includes hammering out with Congress the details of a massive $825 billion bailout.

"They want to have a complete overhaul of this financial-rescue package within days," said ABC News' chief Washington correspondent George Stephanopoulos.

Obama will meet with senior economic advisers in the afternoon to discuss the stimulus package as well as the $350 billion in Troubled Asset Relief Funds that Congress approved at his request last week to stabilize the financial markets.

To underline the urgency of devising an economic plan, the stock market took its biggest ever inauguration day plunge Tuesday, with the Dow Jones industrial average dropping 330 points, and today's headlines warned of a worsening bank crisis.

Iraq is also high on the Day One agenda. In the late afternoon, Obama will meet with his top generals, including Defense Secretary Robert Gates, Chairman of the Joint Chiefs of Staff Adm. Mike Mullen, National Security Adviser Gen. Jim Jones (Ret.) and Gen. David Petraeus, who heads the U.S. Central Command. Joining the meeting via teleconference from Iraq will be U.S. Ambassador to Iraq Ryan Crocker and Gen. Ray Odierno, the top ranking U.S. general in Iraq.

It's not clear whether Clinton will be confirmed as secretary of state in time to sit in on the session.

Obama will be briefed on the status of military operations, and he will command the team to begin making plans to withdraw all U.S. combat troops from Iraq within 16 months.