Currently, Apple's website has a banner indicating that the record has been broken. It also says that viewers should come back later to find out who won the $10,000 prize.
The new mark comes just eight months after the 15 billionth app was downloaded, and slightly more than a year after the 10 billionth app was downloaded.
Things wouldn't be complete without a comparison against Google's Android Market. The Android Market reached 10 billion downloads in December of last year.