The new postage rate becomes effective on Sunday, January 22, 2012. If you stocked up on the Forever Stamp, you're in luck, because they automatically upgrade to the new rate. The new postcard rate will be 32¢ and additional ounces for letters will remain the same @ 20¢. Get your mail off on January 21, 2012, otherwise your mail may be returned for postage due if you forgot about the new rate. The first-class postage last increase was more than 2 1/2 yrs. ago.
The lines may be extremely long on Saturday, January 21, 2012 at the post office, not to mention most typically close at Noon or 1PM so get there early if you have any intentions of stocking up.