Apple has announced that iTMS has now sold over a quarter billion songs:
...music fans have purchased and downloaded more than 250 million songs from the iTunes® Music Store. iTunes users are now downloading one and a quarter million songs per day, which is an annual run rate of almost half a billion songs per year. The iTunes Music Store is now available in fifteen countries, which together represent more than 70 percent of the global music market.
“When we launched the iTunes Music Store we were hoping to sell a million songs in the first six months—now we’re selling over a million songs every day, and we’ve sold over a quarter billion songs in total,” said Steve Jobs, Apple’s CEO. “iTunes is leading the way into the digital music era and together with iPod is changing the way millions of music lovers find and enjoy their music.”