At a rate of 900 apps downloaded per second, Apple is projected to hit 1 billion sometime next Saturday morning (it’s just over 930 million at the time of this post).

Open app marketplaces are a key ingredient in the recent progress of the mobile industry, and Apple started the trend. See the live counter here, including a drawing to win $10 grand in commemoration of the milestone.

Apple has also listed the top 20 app downloads of all time. Usually the app store provides a list of the 100 most popular current apps, so this is a rare look at how they’ve stacked up over time.

Notice that Urbanspoon, one of our pre-season favorites, is 11th on the list out of more than 30,000 apps.