I had heard this was on the horizon, but I didn't pay too much attention to when it was actually going into effect.
As of May 11th the price of stamps will be increasing by .02¢. It will now cost .44¢ to mail a regular old letter. The only way around this is to stock up on Forever stamps now.
In addition to stamps, pretty much every other postal service will be increasing as well. For a full list of the new pricing go HERE.