CNET's FAQ on RealID:

CNET explains how the law will affect you. Some quotes:

"Starting three years from now, if you live or work in the United States, you'll need a federally approved ID card to travel on an airplane, open a bank account, collect Social Security payments, or take advantage of nearly any government service. Practically speaking, your driver's license likely will have to be reissued to meet federal standards."

"What's going to be stored on this ID card?
At a minimum: name, birth date, sex, ID number, a digital photograph, address, and a "common machine-readable technology" that Homeland Security will decide on."

"Why did these ID requirements get attached to an "emergency" military spending bill?
Because it's difficult for politicians to vote against money that will go to the troops in Iraq and tsunami relief."