Congress recently approved raising the federal minimum wage over the next two years. From the current rate of $5.15 per hour, the federal minimum wage will rise to $5.85 per hour on July 24. It will again rise, to $6.55 an hour, on July 24, 2008, and to $7.25 an hour on July 24, 2009. The last increase came in 1997, when the federal minimum wage was at $4.75 an hour.

I compiled a graph a while ago comparing the historic value of the federal minimum wage in current and constant dollars. The Fair Labor Standards Act of 1938 established minimum wage coverage, but the graph only shows data from 1950 onward for simplicity. In constant dollars, the federal minimum wage peaked in 1968; the rate then of $1.60 per hour would be $9.45 per hour in today's dollars.

Links:
"Congress Approves Minimum Wage Hike" (Washington Post)
U.S. Dept. of Labor Wage and Hour Division
Minimum Wage Laws in the States (U.S. Dept. of Labor)--Interesting graphic showing how each state's minimum wage rate compares to the federal wage rate.
What Is a Dollar Worth? (Federal Reserve Bank of Minneapolis)

Note: Graph labels corrected September 13, 2007.