How does Social Security reform work?

That depends on the reformer. The reform George Bush is advocating would incorporate some sort of private savings account. Instead of Social Security taxes being taken out of your paycheck and "saved" by the government on your behalf, to be given back to you at the time and in the manner in which future politicians decide, you would be allowed to invest your own money for your own retirement. For more information and specifics on one a few of the most popular plans, see the Cato Institute's Project on Social Security Choice: http://www.socialsecurity.org/