Offical post from USPS.com:
On
May 11 the price for a 1-ounce First-Class Mail stamp will increase
from 42¢ to 44¢. Prices for other mailing services — Standard Mail,
Periodicals, Package Services (including Parcel Post), and Extra
Services — will also change. The average increase by class of mail is
at or below the rate of inflation as measured by the Consumer Price
Index.
See Complete Price List (PDF)
Customers can use their Forever Stamps — regardless of when
purchased — to mail 1-ounce letters after the price change, without the
need for additional postage. Forever Stamps are widely available
through Post Offices, commercial retail outlets such as grocery stores,
and online.
Prices
for mailing services will continue to adjust each May. Prices for most
shipping services, including Express Mail and Priority Mail, were
adjusted in January and will not change in May.