Minimum Wage

I have seen many calls for an increase in the minimum wage. Both nationally and on the state level. George Allen has been criticized for his vote against increasing the Federal Minimum wage. I wonder though, can anyone show me the clause in either the United States Constitution or the Constitution of the Commonwealth of Virginia that gives the Government the power to set the price of services? And make no mistake, the wage you recieve from your employer is the price he is willing to pay and the price you are willing to recieve for services you have sold to your employer.