Congress needs to act now on the proposed economic package to provide relief to American taxpayers and help get the country back on its feet, President Bush told a rowdy audience at the U.S. Chamber of Commerce on Tuesday.

"You understand that our duty here in Washington is to set pro-growth policies in place that reward and respect Americans who work hard and take risks," Bush told a loudly cheering crowd made up of the Tax Relief Coalition (search).

Tuesday's speech was just one more sign that the commander in chief seems to have made the transition from speaking exclusively to military installations and defense contractors to addressing pro-business groups in an effort to push his tax-cut plan.

On Monday, Bush spoke with a group of small business owners in Little Rock, Ark. It was a departure from weeks of talking to plant workers.

Key congressional committees are working this week to flesh out the details of a tax-cut proposal. The House Ways and Means Committee begins debate Tuesday on the 10-year, $550 billion package the House approved as a framework for tax cuts last month.

The Senate Finance Committee (search) will debate a smaller package Thursday. A committee spokeswoman said the size and shape of the proposal is likely to change during that time. But Senate Republicans will have a much harder time getting a package worth more than $350 billion approved, since some moderate Republicans have said they will oppose anything more.

GOP leaders looking to increase that sum are pointing to reductions in spending increases to offset larger tax cuts. The White House has already conceded that it would be satisfied with $550 billion and urged the audience to encourage lawmakers to pass that bill.

"You're here at just the right time," Bush said. "They're trying to figure out what course to take. I'm glad you're bringing your voice to the halls of Congress."

Using the 6 percent unemployment rate released last week to justify his cuts, the president said his plan would create 1 million new jobs by the end of 2004.

"I've submitted a good strong plan to help us meet that goal," Bush said. "We need aggressive action out of the U.S. Congress now."

Bush also stressed the important role small business owners play in the entire U.S. economy. He said his plan will help give those businesses relief and will spur investment.

And the president said the U.S. tax code should support small businesses that want to invest in the future. The Bush plan would triple the amount of new equipment that small businesses can expense, from $25,000 to $75,000 per year, and index that to inflation.

To critics who say his plan only helps the rich, Bush shot back that his proposal to eliminate the double taxation of dividends would create over 400,000 new jobs.

He added: "Good tax policy ripples throughout our economy," citing examples of how small business owners are taking risks to create jobs — risks that are paying off.

Bush has said in past speeches that he wants a bill on his desk by Memorial Day, ready for his signature. Earlier in the day, White House spokesman Ari Fleischer praised Congress for moving in a "very timely fashion" on the proposals, which should be through the respective committees by next week.

The 20-month "relentless campaign against global terror," combined with a recession that began in the summer of 2000, the Sept. 11 terrorist attacks and the war, has taken it's toll on the U.S. economy, Bush said.

"The American economy has faced one challenge after another over the past several years," the president said. But he added, "we will spend whatever's necessary to win the war."

Fox News' Liza Porteus and James Rosen and The Associated Press contributed to this report.